Don’t recognize that debt? Here’s what to do.

Debt collectors make up to one billion contacts with consumers each year. It’s their job to make sure they’re collecting from the right people. But sometimes, they reach the wrong person. Other times, they’re actually part of a fake debt collection scam.

If you don’t recognize a debt, here’s what you can do:

Find out who you’re dealing with. Ask for the collector’s name, the company’s name, and its address and phone number. Legitimate collectors will provide this information.

Don’t give additional personal information. The collector might ask you to confirm personal information. If the collector has the wrong information, like an address or phone number you’ve never used, don’t correct the mistake with the right information. And don’t give any other personal information. If it’s not your debt, but the collector now has the right personal information for you, it could be harder for you to dispute the debt later.

Refuse to discuss the debt until you get a “validation notice.”Collectors must send you a written notice. It tells you how much money you owe, the name of the creditor, and what to do if you don’t think you owe the money. This notice might help you figure out if you owe the debt.

Do your own detective work. Reach out to the company the collector says is the original creditor. They might help you figure out if the debt is legitimate – and if this collector has the right to collect the debt. Also, get your free, annual credit report online or at 877-322-8228 and see if the debt shows up there.

Dispute the debt in writing. If you think you don’t owe some – or all – of the debt, or you just don’t recognize it, send the collector a letter disputing it. Be as specific as possible about why you think the debt is wrong – but give as little personal information as possible. Once you get the validation notice, you have 30 days to send this letter.

By law, the collector then must stop contacting you – though the debt doesn’t go away. But, if the collector sends you written verification of the debt, they can start contacting you again.

And, if there’s incorrect information on your credit report, dispute that, too.