How you respond to a complaint letter depends entirely on what kind of complaint it is. A business or consumer grievance calls for a prompt, professional reply aimed at resolving the dispute. A legal complaint filed in court comes with a summons and a hard deadline: 21 days to file a written Answer in federal court, 60 days if you waived formal service, or whatever the summons specifies in state court. Miss that deadline and the plaintiff can win by default.
So the first question is which one you’re holding.
Business Complaint or Lawsuit? How to Tell
A legal complaint arrives with a summons. The summons names a court, carries a case number, identifies you as the defendant, and orders you to respond by a specific date. It typically reaches you through a process server, by certified mail, or alongside a waiver-of-service request from the plaintiff’s attorney. If any of those apply, you’re being sued and a court is tracking your clock.
A business complaint letter comes directly from a customer, vendor, or organization. It may demand a refund, request corrective action, or threaten litigation, but it does not carry a court-imposed deadline. These letters still deserve attention. Ignoring a legitimate grievance can escalate the dispute, damage your reputation, and lead to the lawsuit the sender was hinting at.
Responding to a Business Complaint Letter
When the complaint is a grievance rather than a court filing, the goal is to resolve it before it escalates. Acknowledge the letter quickly, even if you need more time to investigate. A brief reply confirming receipt and promising a substantive answer keeps the sender from feeling ignored.
Once you understand the facts, write a response that addresses each point raised. If the complaint has merit, say so plainly and explain what you plan to do about it. If you disagree, lay out your reasoning and supporting evidence without being combative. Propose a specific remedy where you can: a refund, a replacement, a corrected invoice, a service credit. Keep the tone professional and empathetic. Most business disputes settle at this stage when the response shows genuine engagement rather than a form-letter brush-off.
Your Deadline to Respond to a Lawsuit
In federal court, you have 21 days after being formally served with a summons and complaint to file your written Answer. If the plaintiff sent you a waiver-of-service request and you signed and returned it, you get 60 days from the date the request was sent, or 90 days if you are outside the United States.1Legal Information Institute. Federal Rules of Civil Procedure Rule 12 – Defenses and Objections Waiving service does not waive your defenses. It saves both sides the cost of a process server, and the court rewards that cooperation with extra time.
State courts set their own deadlines. Some states give you 20 days, others allow 30, and a few vary the number depending on how you were served. The summons almost always spells out the exact count, so read it carefully. When you calculate the deadline, exclude the day you were served and start counting the next calendar day. If the deadline falls on a weekend or court holiday, it rolls to the next business day.
Getting More Time
If 21 days isn’t enough, you have options. The simplest is to contact the opposing attorney and ask for a stipulated extension. Many attorneys will agree to a reasonable first extension as a professional courtesy. Put the agreement in writing and, depending on local rules, file it with the court.
If the other side refuses, you can file a motion asking the court for extra time. Under the federal rules, a court can grant more time for good cause if you ask before the deadline expires. Even after it passes, the court can still grant an extension if your failure to act resulted from excusable neglect, though that is a harder standard and not something to plan around.2Legal Information Institute. Federal Rules of Civil Procedure Rule 6 – Computing and Extending Time
Preserve Your Evidence Right Away
The moment you receive a legal complaint, you have a duty to preserve documents, electronic files, and physical evidence that could be relevant. The obligation kicks in as soon as you reasonably anticipate litigation, which is at the latest the day you are served and possibly earlier if a demand letter came first.
In practice, that means you stop deleting emails, stop shredding files, and suspend any automatic document-destruction policies your business runs. Relevant evidence includes contracts, invoices, text messages, photographs, internal memos, and any communications with the person suing you. If you destroy or lose evidence you should have preserved, the court can impose sanctions ranging from unfavorable evidentiary rulings up to entering judgment against you, particularly if the destruction was intentional. Organize what you have chronologically against the events described in the complaint. The work pays off in both your Answer and later discovery.
Drafting the Answer
Your Answer responds to every allegation in the complaint, point by point. Federal rules require you to go through each numbered paragraph and do one of three things: admit the allegation, deny it, or state that you lack sufficient knowledge to admit or deny. That last option functions as a denial.3LII / Legal Information Institute. Federal Rules of Civil Procedure Rule 8 – General Rules of Pleading If an allegation is partly true and partly false, admit the accurate portion and deny the rest.
Resist the urge to write a narrative essay. Courts want concise, numbered responses that mirror the complaint’s structure. Most judicial districts publish fill-in Answer forms on their websites; using one ensures the caption correctly identifies the court, the parties, and the case number. Keep the language factual and emotionally neutral. The strongest Answers tie each denial to a specific piece of evidence rather than blanket-denying everything, which courts view skeptically.
Affirmative Defenses
An affirmative defense says, in effect, “even if everything you claim is true, I’m not liable for a separate legal reason.” Common examples include an expired statute of limitations, the plaintiff’s own negligence contributing to their injury, a prior release or settlement, and fraud or duress affecting the underlying agreement. Federal rules list nearly twenty recognized affirmative defenses, and any you fail to raise in your Answer can be waived permanently.4Legal Information Institute (LII) / Cornell Law School. Federal Rules of Civil Procedure Rule 8 – General Rules of Pleading When in doubt, include it. You can withdraw a defense later, but you often cannot add one you forgot.
Counterclaims
If you have your own claims against the person suing you, the Answer is usually the place to raise them. A counterclaim that arises from the same facts as the plaintiff’s lawsuit is compulsory, meaning you must include it or risk losing the right to bring it later.5Legal Information Institute (LII) at Cornell Law School. Federal Rules of Civil Procedure Rule 13 – Counterclaim and Crossclaim For example, if a contractor sues you for unpaid invoices and you believe the contractor’s defective work caused you damages, that damage claim is compulsory because it stems from the same project.
Claims unrelated to the plaintiff’s lawsuit are permissive. You can fold them into the same case for convenience, but you won’t lose them by filing separately. The distinction matters most for compulsory counterclaims, where the penalty for forgetting is severe: the claim is barred once the case reaches judgment.
Filing a Motion to Dismiss Instead
Before drafting an Answer, consider whether the complaint has a fatal procedural or legal flaw. A motion to dismiss challenges the lawsuit on grounds like the court lacking jurisdiction over you, the case being filed in the wrong location, defective service of the summons, or the complaint failing to describe a legally recognized claim.6Legal Information Institute (LII). Federal Rules of Civil Procedure Rule 12 – Defenses and Objections This motion must be filed before your Answer.
Filing it pauses the Answer deadline. If the court denies the motion, you get 14 days from that ruling to file your Answer.7Legal Information Institute (LII) / Cornell Law School. Federal Rules of Civil Procedure Rule 12 – Defenses and Objections A frivolous motion to dismiss will not impress the judge and only delays the inevitable. The strongest candidates are cases where the court plainly lacks jurisdiction or where the complaint, taken at face value, does not state a viable legal theory.
Serving and Filing Your Response
Getting your response where it needs to go involves two separate steps: serving a copy on the opposing party and filing the original with the court. If the plaintiff has an attorney, serve the attorney rather than the plaintiff directly.8Cornell Law School | Legal Information Institute. Federal Rules of Civil Procedure Rule 5 – Serving and Filing Pleadings and Other Papers
Acceptable service methods include hand delivery, mailing to the person’s last known address, or sending electronically through the court’s e-filing system if the recipient is a registered user. Service by mail is complete on the date of mailing. Most federal courts now require electronic filing, which generates a timestamped confirmation receipt. Save it.
When you file electronically, no separate certificate of service is needed because the court’s system handles notification. If you serve by any other method, include a certificate of service, which is a short statement identifying who you served, how, and when.8Cornell Law School | Legal Information Institute. Federal Rules of Civil Procedure Rule 5 – Serving and Filing Pleadings and Other Papers Keep copies of everything: the filed Answer, supporting documents, the confirmation receipt or stamped copy from the clerk, and any certificate of service. These records prove you met your deadline if the question ever comes up.
What Happens If You Miss the Deadline
Missing a response deadline is one of the most consequential mistakes in civil litigation. The plaintiff can ask the court clerk to enter a default against you, which is a formal notation that you failed to defend the case. The plaintiff can then move for a default judgment, meaning the court awards what they asked for without you ever presenting your side.9Cornell Law School | Legal Information Institute (LII). Federal Rules of Civil Procedure Rule 55 – Default and Default Judgment
If the plaintiff’s claim is for a specific dollar amount, the clerk can enter judgment without a hearing. For other claims, the court holds a hearing to determine damages, but you may not be invited to participate if you never appeared. Either way, the result is a legally enforceable judgment against you, potentially including the full amount demanded plus costs.
A default is not always permanent. The court can set aside an entry of default for good cause before final judgment. Setting aside a default judgment after it becomes final is harder and requires grounds under the federal rules such as mistake, surprise, or excusable neglect, with the motion filed within a reasonable time and no more than one year after the judgment.10Legal Information Institute (LII) / Cornell Law School. Federal Rules of Civil Procedure Rule 60 – Relief from a Judgment or Order Courts look at whether you have a plausible defense, how quickly you acted once you realized the problem, and whether reopening would unfairly harm the plaintiff. None of that is guaranteed. The safest approach is to never miss the deadline.
When You Need a Lawyer
Individuals can represent themselves in federal and state court, but the complexity of many lawsuits makes legal help worth serious consideration. If the complaint involves a large sum of money, complicated legal theories, or claims you do not fully understand, hiring an attorney is the most effective way to protect your interests. An experienced litigator spots affirmative defenses and counterclaims you might miss, and those omissions can permanently waive your rights.
If you are a business entity rather than an individual, this is not optional. Corporations, partnerships, and LLCs cannot represent themselves in federal court. They must appear through a licensed attorney. Filing an Answer on behalf of your company without one can get the filing rejected or stricken, which puts you right back on the path to a default judgment.