How to Dispute an Invoice: Legal Grounds, Deadlines, and Letters

To dispute an invoice, send a written challenge to the right address before your deadline runs out, backed by documents that show exactly what’s wrong and how much you’re contesting. The deadline is the part that catches people. If you paid by credit card, federal law gives you only 60 days from the date the statement was mailed. If you’re a business challenging a bill for goods or services, your window depends on your contract and state law, but acting fast still protects your position and preserves your evidence. Knowing how to dispute an invoice means matching your situation to the right legal protection before that clock closes.

Figure Out Which Law Applies to Your Dispute

The legal basis for your challenge depends on what you bought, how you paid, and whether you’re a consumer or a business. This determines your deadline and your leverage, so settle it before you write anything.

You Paid by Credit Card

The Fair Credit Billing Act covers billing errors on credit card accounts: wrong amounts, charges for undelivered goods, items that arrived damaged, unauthorized transactions, charges that differ from what you agreed to pay, and statements the creditor failed to send to your current address.¹ If you paid by credit card, this is your strongest tool.

A separate provision lets you raise claims against your card issuer based on problems with the merchant’s goods or services, provided the original transaction exceeded $50 and occurred in your home state or within 100 miles of your mailing address. Those geographic and dollar limits don’t apply when the card issuer and the merchant are the same company or affiliated.²

You Bought Goods

When a business receives products that don’t match the purchase order, the Uniform Commercial Code applies. Under UCC Section 2-601, if goods fail to conform to the contract in any way, the buyer can reject everything, accept everything, or accept the conforming units and reject the rest.³ Wrong quantities, defective items, or substituted products all give you grounds to dispute the invoice for the nonconforming portion. The UCC has been adopted in some form by every state, though details vary.

One catch: if you’ve already accepted the goods by using them, failing to inspect them within a reasonable time, or telling the seller you’ll keep them, you lose the right to reject. You can still recover damages for the nonconformity, but you must notify the seller of the breach within a reasonable time after discovering it, or you’re barred from any remedy.

You Hired Someone for a Service

The UCC doesn’t cover service contracts. When you hire someone and the result falls short, common law contract principles govern. The key concept is substantial performance. If the provider completed the job in a way that fulfills the essential purpose of the contract despite minor shortcomings, courts generally won’t let you refuse the entire invoice. You’d be entitled only to a reduction covering the cost to fix whatever fell short.

If the work was so deficient that it doesn’t serve the contract’s purpose at all, that’s a material breach, and you have stronger grounds to refuse the full amount. The line between a minor shortcoming and a material breach is where most service-invoice disputes live, and it’s fact-specific. Courts look at the harm caused by the deviation, what the parties expected, and whether the provider’s failure was intentional. Contracts that mix goods and services get sorted by which element was the primary purpose.

The Deadlines You Cannot Miss

Under the Fair Credit Billing Act, you must send a written dispute within 60 days after the creditor mailed or delivered the billing statement containing the error.¹ Miss that window and you lose your federal protections, even if the charge is clearly wrong. Sixty days sounds generous until a statement sits unopened or you only notice the error weeks later.

The notice has to go to the address the creditor designated for billing inquiries, not the address where you send payments. These are often different, and sending your dispute to the payment address doesn’t satisfy the statute.⁴ The billing inquiries address is usually printed on your statement.

For non-credit-card invoices, there’s no single federal deadline. Your timeframe depends on your contract terms, the state statute of limitations for breach of contract (typically three to six years in most states), and whether the UCC’s “reasonable time” notice requirement applies to a goods transaction.⁵ A longer statute of limitations is no reason to wait. The sooner you dispute, the stronger your position and the easier it is to gather evidence.

Build Your Evidence File Before You Write

Before drafting anything, assemble a file that makes your case obvious to someone who knows nothing about the transaction. Start with the original invoice and the contract, purchase order, or written quote that established the agreed-upon price and scope. Line them up side by side. Every discrepancy between what was agreed and what was billed is a potential dispute point.

Pull your bank and credit card statements to check whether partial payments were already processed or whether you were billed twice for the same charge. Save email threads with the vendor’s sales or account team, especially messages where pricing, delivery dates, or scope of work were discussed. Those contemporaneous communications carry more weight than after-the-fact summaries because they show what both sides understood at the time.

For goods disputes, document the condition of what arrived. Timestamped photos, delivery receipts noting damage, and communications with the carrier all help. For service disputes, keep records showing what work was actually completed versus what the contract specified. If you hired someone else to fix an incomplete job, that contractor’s invoice is evidence of the cost to cure.

Mark up a copy of the disputed invoice with each contested line item highlighted and a brief note explaining why it’s wrong. That marked-up copy becomes the backbone of your letter and gives the billing team a clear roadmap instead of forcing them to guess which charges you’re challenging.

Write the Dispute Letter

Your letter needs to do three things: identify you and the transaction, state exactly what’s wrong, and tell the recipient what you want done. For credit card disputes, the statute requires your name, account number, an indication that the statement contains a billing error, the dollar amount in question, and your reasons for believing there’s an error.¹ Covering all five is non-negotiable if you want federal protection.

Be specific about dollar amounts. If you agreed to pay $500 for a service and received an invoice for $750, state that you’re disputing $250 and explain why. “Services not rendered,” “quantity differs from purchase order,” or “price exceeds written quote dated [date]” each give the reviewer something concrete to investigate. Vague complaints like “this seems too high” invite dismissal.

Keep the tone professional and factual. Attach copies of your supporting documents, not originals, and reference each attachment in the body of the letter. If you’re disputing a non-credit-card invoice, the letter doesn’t need to follow the FCBA format, but using the same information makes it harder for the vendor to claim they didn’t understand the dispute.

Send It the Right Way

Send your letter by certified mail with a return receipt requested. This creates a dated paper trail proving the creditor received your notice, which matters if the dispute escalates and the timeline is questioned. For credit card disputes, use the billing inquiries address on your statement, not the payment address.⁴

Many vendors and card issuers also accept disputes through online portals. If you go that route, screenshot the confirmation page and save any confirmation number or email. For credit card billing errors specifically, a written notice is what the statute contemplates, so sending a physical letter in addition to the online submission is the safer play.

Keep a log with the date you mailed the letter, the tracking number, the delivery date on the return receipt, and the names of anyone you spoke with. That log becomes your timeline if the dispute drags on.

What the Creditor Must Do Next

For credit card disputes, the FCBA imposes a structured timeline. The creditor must acknowledge your dispute in writing within 30 days of receiving it, unless they resolve the issue within that same 30 days. They must then complete their investigation and either correct the error or explain why they believe the bill is accurate within two billing cycles, and no more than 90 days after receiving your notice.¹

While the investigation is pending, you can withhold payment on the disputed amount and any related finance charges. You’re still responsible for paying the undisputed portion on time.⁴ The creditor cannot take legal action to collect the disputed amount during this period. If the investigation finds the charge was an error, related interest and late fees must be removed.

Credit Reporting Protections

During the investigation, the creditor cannot report the disputed amount as delinquent to credit bureaus or threaten to do so. If the creditor concludes after investigation that you still owe the money and you continue to dispute it, they can report the amount, but they must also report that the amount is in dispute and tell you the name and address of every party they reported the delinquency to.⁶ Once the dispute is resolved, the creditor must report that resolution to everyone they previously notified.

Separately, under the Fair Credit Reporting Act, if you dispute information directly with a credit bureau, the bureau must note the dispute on your file and either verify, correct, or delete the item.⁷ Filing disputes with both the creditor and the credit bureau gives you overlapping protections.

Paying “In Full” to Settle a Disputed Amount

If the fight is over the amount owed rather than whether anything is owed at all, you can sometimes resolve it by sending a check for the amount you believe is correct with a clear, conspicuous note stating the check is tendered as “payment in full” for the disputed claim. Under UCC Section 3-311, if the vendor cashes that check, the entire claim may be discharged, meaning they can’t come back for the balance.⁸

This only works when the amount was genuinely in dispute or unliquidated. It won’t discharge a debt where both sides agree on the amount but you just don’t want to pay. There’s also a carve-out for organizations: if the vendor previously designated a specific person or address for handling disputed payments and your check went somewhere else, cashing it doesn’t create an accord and satisfaction. The vendor can also undo it by refunding the check amount within 90 days.⁸

If a Debt Collector Shows Up

When a disputed invoice gets handed off to a debt collector, a different federal law applies. Under the Fair Debt Collection Practices Act, the collector must send you a written notice within five days of first contacting you, including the amount of the debt and the name of the creditor.⁹

You then have 30 days from receiving that notice to dispute the debt in writing. If you do, the collector must stop all collection activity until they send you verification of the debt or a copy of any judgment. If you don’t dispute within 30 days, the collector can treat the debt as valid.⁹ That doesn’t automatically mean you owe it; it just means the collector no longer has to pause while you figure things out. You can still raise defenses later, but you’ve lost leverage.

If you already disputed the underlying invoice with the original vendor, send that documentation to the collector along with your written dispute. Collectors sometimes pursue invoices that have already been resolved, and your earlier correspondence is the fastest way to shut that down.

If the Dispute Stalls

If the creditor denies your dispute or ignores it, you have options, though they require more effort.

Mediation. A neutral third party helps both sides negotiate a compromise. It’s cheaper and faster than court, and many contracts include mediation clauses that require you to try it before filing suit.
Small claims court. Most states allow claims ranging from $2,500 on the low end to $25,000 at the high end, depending on jurisdiction. Filing fees are relatively modest, you typically don’t need a lawyer, and the process is designed to be accessible.
CFPB complaints. For financial products and credit-related disputes, you can submit a complaint to the Consumer Financial Protection Bureau. The agency forwards complaints to companies and tracks their responses.¹⁰

Watch the statute of limitations. In most states, the window for filing a breach-of-contract lawsuit falls between three and six years, though some states allow longer.⁵ Making a partial payment or even acknowledging you owe the debt can restart the clock in some states, so be careful about what you say or pay while deciding whether to escalate.

Invoices to Federal Agencies Work Differently

If you’re a vendor billing a federal agency, a separate framework applies. Under the Prompt Payment Act, when an agency determines a submitted invoice isn’t proper, it must return the invoice within seven days and explain what’s wrong.¹¹ If the agency simply pays late on a proper invoice, it owes interest automatically at a rate set every six months. For the first half of 2026, that rate is 4.125 percent per year.¹² The penalty is paid whether or not the vendor asks for it.

When the dispute is over the amount owed or whether contract terms were met, Prompt Payment Act interest stops accruing. The dispute instead gets routed through the Contract Disputes Act process, and any interest for the dispute period is resolved through that separate channel.¹¹

1
Office of the Law Revision Counsel. 15 U.S. Code 1666 – Correction of Billing Errors
2
Office of the Law Revision Counsel. 15 U.S. Code 1666i – Assertion by Cardholder Against Card Issuer of Claims and Defenses
3
Cornell Law School. UCC 2-601 – Buyer’s Rights on Improper Delivery
4
Federal Trade Commission. Using Credit Cards and Disputing Charges
5
Consumer Financial Protection Bureau. Can Debt Collectors Collect a Debt That’s Several Years Old
6
Office of the Law Revision Counsel. 15 U.S. Code 1666a – Regulation of Credit Reports
7
Office of the Law Revision Counsel. 15 U.S. Code 1681i – Procedure in Case of Disputed Accuracy
8
Cornell Law School. UCC 3-311 – Accord and Satisfaction by Use of Instrument
9
Office of the Law Revision Counsel. 15 U.S. Code 1692g – Validation of Debts
10
Consumer Financial Protection Bureau. Submit a Complaint
11
Office of the Law Revision Counsel. 31 USC Ch. 39 – Prompt Payment
12
Federal Register. Prompt Payment Interest Rate; Contract Disputes Act