A mistake on your credit history could just be an error by the credit agency or a vendor. However, it could also indicate identity theft or fraud. Contact the vendor right away, alert them, and change the information. You should also contact the three major credit bureaus (Equifax, TransUnion, Experian) and alert them to change their records. Each of the three bureaus offers a free copy of your credit report annually at annualcreditreport.com.