1. In the sample letter, fill in your personal information. Use this sample letter to dispute mistakes on your credit report.Fix credit report errors with our easy guide on writing a credit dispute letter. Start improving your credit score today! (Must be on Financial Institution Letterhead). See a sample credit dispute letter below. Get your free copy here! Address your letter: Write the date and lender's address at the top of the explanation letter, then address the lender or lending institution. Get your free copy here! Keep your originals.