Send the letter via with a "return receipt requested" to prove they received it.
Under the Fair Debt Collection Practices Act (FDCPA) , third-party collectors must stop contacting you once they receive this written notice. Credit Problem
A clear, factual explanation of why the information is wrong (e.g., "The account was closed by me, not the lender"). A request for the item to be removed or corrected. Send the letter via with a "return receipt