This e-book provides templates for 21 most effective credit and collection letters that will help you communicate better with your customer. Download our sample letter and instructions to submit a dispute with an information furnisher.Download our sample letter and instructions to submit a dispute. Learn how to write an effective collection dispute letter with our guide and templates. Example: Selena falls behind on her credit card payments, and after several months of missed payments, the card company marks the account as a charge-off. Office of Business Opportunity. Documents and Forms. If you want to write a letter of explanation for a mortgage lender, you'll need to provide clarifying information about your finances. 1. In the sample letter, fill in your personal information.