Date of original charge off or delinquency. • Verification that this debt was assigned or sold to collector.Include your name, address, phone number, and email address at the top of the letter. Give the other party a specific date to respond to your letter. Seven to ten days is typical. How to use this sample letter: 1. Read the background below. 2. Washington state driver's license or ID number. (Form SM-11) Letter of Credit no. 1. In the sample letter, fill in your personal information.