A credit dispute letter includes personal information and enclosures that help credit bureaus investigate mistakes. Use this sample letter to dispute incorrect or inaccurate information that a business supplied to credit bureaus.Individual and corporate taxpayers may claim a credit against their tax liability for the donation of land or an interest in land. Mortgage lenders might request a letter of explanation for various red flags that come up in underwriting. Learn how to write one, and download a template. 1. In the sample letter, fill in your personal information. Sample Letter of Credit. Supporting Documents. Below is a sample letter to help you craft your own letter. Send the letter via certified mail and keep the return receipt for your records.