If a debt collector insists that you co-signed the account but you believe you did not, you may request that the collector provide evidence, such as a copy of a contract that you signed. Credit card issuers usually report authorized users’ status to the credit bureaus. You may be able to satisfy the debt collector that you were just an authorized user by showing the collector the relevant portion of your credit report. You can obtain a free copy of your credit report once each year at each of the three nationwide credit bureaus at www.annualcreditreport.com , by calling 1-877-322-8228, or by mailing a request.