If you disagree with an individual or a company, and informal efforts to resolve your dispute fail, you should write a demand letter. 1. In the sample letter, fill in your personal information.Washington Free Debt Validation Letter. Use our debt validation letter to request the validity of a debt. The purpose of credit explanation letter is to acknowledge that you had a challenge in your previous life with your credit or maybe currently. How to use this sample letter: 1. Read the background below. 2. Sample Letter of Credit in MS Word format. A demand letter is an official notice requesting money, possession of assets, or action on a legal matter. This sample letter explaining credit problems will help you focus your efforts when appealing to a property manager for an apartment.