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Disputing a Debt You Don't Owe in Ontario: How to Fight a Wrong Collection Claim

Being chased for a debt that isn't yours or was already paid? How to formally dispute a wrong collection claim in Ontario, step by step.

Litigation5 min readTSLBy the Treadstone Law team · OntarioUpdated 2026-07
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Key takeaways
  • Before disputing anything, ask the collector or creditor to put the debt's details in writing: the original creditor, the account number, the amount claimed, and how that amount was…
  • - [ ] Do you recognize the original account this debt is supposedly based on?
  • Send a written dispute setting out specifically why you say the debt is wrong — not owed, already paid, or inaccurately calculated — along with copies of your supporting records.

Being pursued for a debt that simply isn't yours — because it was already paid, the amount is wrong, or it never belonged to you in the first place — is more common than most people expect, and more frustrating to fix than it should be. Collection errors happen: records get mismatched, old balances get miscalculated, accounts get resold with outdated information attached.

Disputing a debt you don't owe in Ontario is not just a matter of telling the collector "that's wrong" over the phone and hoping it goes away. It usually takes a deliberate, documented process, especially once the matter has escalated toward — or into — a lawsuit.

This guide walks through how to build and raise that dispute properly.

Step 1 — Get the Details in Writing

Before disputing anything, ask the collector or creditor to put the debt's details in writing: the original creditor, the account number, the amount claimed, and how that amount was calculated. A vague verbal claim is hard to dispute effectively; a written breakdown gives you something concrete to check against your own records.

Step 2 — Compare Against Your Own Records

Keep copies of anything that supports your position: payment confirmations, bank statements, prior correspondence, settlement letters.

Step 3 — Dispute in Writing, Clearly and Promptly

Send a written dispute setting out specifically why you say the debt is wrong — not owed, already paid, or inaccurately calculated — along with copies of your supporting records. A clear, prompt, documented dispute is far more useful later than a vague objection made only once, informally, and never followed up.

Step 4 — Don't Let a Dispute Distract You From a Court Deadline

If the dispute escalates into an actual lawsuit, disputing the debt with the collector directly is not a substitute for responding to the claim itself within your court deadline. These are two different tracks: informal dispute and formal legal response. If you are served with a claim, that deadline governs, regardless of where an informal dispute stands.

Turning a Dispute Into a Formal Legal Defence

If you're not yet suedIf you've been served with a claim
Send a written dispute with supporting records; keep a paper trailFile a formal defence within your deadline, raising the same dispute
Follow up if you don't get a substantive responseAttach or reference your supporting documents in your response
Consider getting advice if the debt is significant or the collector won't engageDon't wait for the dispute to be "resolved" informally before responding

What If the Collector Won't Budge?

Sometimes a collector maintains its position even against solid contrary evidence. At that point, your options generally include continuing to formally dispute it, waiting to see whether the matter proceeds to a lawsuit (where you can raise the dispute as a defence), or getting a lawyer involved to press the point directly with the collector or the underlying creditor.

Common Reasons a Debt Turns Out to Be Wrong

Frequently asked questions

Does disputing a debt stop collection calls?

Not automatically, though a clear written dispute with supporting evidence can sometimes prompt a collector to pause while it investigates. If contact becomes unreasonable or abusive regardless, that raises separate concerns worth documenting.

What if I already paid the debt but lost the receipt?

Look for alternative proof: bank or credit card statements, email confirmations, or correspondence referencing the payment. A missing receipt is not fatal to a dispute if other records can establish the payment happened.

Can I be sued over a debt I've already formally disputed?

Yes — disputing a debt with a collector does not legally prevent a lawsuit from being filed. If you are served, you still need to file a formal defence within your deadline, using the same evidence that supported your earlier dispute.

What if the debt belongs to someone with a similar name to mine?

That is a recognized problem, sometimes described as mistaken identity, and it needs to be raised directly and specifically — both with the collector and, if it comes to it, in a formal defence — rather than assumed to sort itself out.

This article is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.

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