Sued for Someone Else's Debt in Ontario: Fighting a Mistaken-Identity Collections Claim

There's a particular kind of alarm that comes from opening a lawsuit that names you, over a debt you've genuinely never had anything to do with. It happens more often than people assume — a shared name, an old address linked to a different tenant, a data-entry error carried forward through multiple resales of an old account. Being sued for someone else's debt in Ontario is disorienting, but it is also a fixable problem, provided you respond properly and promptly.

The single biggest risk in a mistaken-identity case is not the underlying error — it's staying quiet because the claim feels so obviously wrong that surely it will "sort itself out." It won't, on its own. This guide covers how these mix-ups happen and what to actually do about one.

How Mistaken-Identity Claims Happen

• Shared or similar names. Common names, or names that match closely enough, can get attached to the wrong person's file, especially through older or less careful record systems.
• Old address links. A debt tied to a previous tenant or a prior occupant of an address can sometimes follow the address rather than the actual person.
• Data carried through resales. As debts get sold from one buyer to another, small errors in the underlying records can get copied forward, and sometimes compounded, with each transfer.
• Identity theft. In some cases, someone else genuinely opened an account using your identifying information without your knowledge.

What to Do If You've Been Served

1. Don't ignore it, however obviously wrong it seems. A claim doesn't stop being a legal proceeding just because you know it's mistaken — if you don't respond, the plaintiff can generally still obtain a default judgment against you.
2. Confirm your identifying details against what's on the claim. Compare your full name, date of birth, and any address history against what's alleged, and note every discrepancy.
3. Gather proof of who you actually are and where you've actually lived. Government identification, address history, and anything else that draws a clear line between you and the actual debtor.
4. File a formal defence within your deadline, stating plainly that the debt does not belong to you and setting out why.
5. Notify the plaintiff or its lawyer directly, in writing, once you've filed — sometimes a well-documented mistaken-identity claim gets discontinued once the error is clearly demonstrated, without needing to go all the way to trial.

If Identity Theft Is Involved

A mistaken-identity claim caused by an address or name mix-up is different from one caused by someone else using your actual identity to open an account. If you suspect identity theft, that typically calls for additional steps beyond just defending the lawsuit — including reporting the fraud through the appropriate channels and monitoring your credit file — on top of formally disputing the specific claim against you.

Documents Worth Gathering

• [ ] Government-issued identification confirming your full legal name and date of birth
• [ ] Proof of your address history, especially around the dates the debt supposedly arose
• [ ] Any prior correspondence from the collector or creditor, including anything sent to a different name or address
• [ ] A credit report, if identity theft is a possibility, to check for other unfamiliar accounts

Why Responding Promptly Matters More Than Being "Obviously" Right

It can feel unnecessary to formally respond to a claim that seems clearly mistaken. But courts generally proceed based on what's actually filed, not on what should be obvious from the outside. A default judgment entered against the wrong person because they didn't respond is a real, and realistically difficult, problem to later unwind — far harder than filing a defence would have been in the first place.

Frequently asked questions