Experian Credit Reporting Complaint

Experian Credit reporting department,

Credit monitoring or identity protection Billing dispute North Carolina

I have gotten a letter from a debt collector for a loan outstanding that I never had. I tried to tell them twice, that this is not my account, nor have I ever had a loan not paid. The debt collector 's name is, - - -, NJ. I called them and told them this is not mine, nor did I see it on my credit reports in past, so apparently they are using my name and old address on the claim. What can you do about this, it seems they just want to harass me no matter what.