1. In the sample letter, fill in your personal information. A 609 letter is a credit repair method that requests credit bureaus to remove erroneous negative entries from your credit report.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. Where do I send my Form REG-4-D? Mail your completed Form REG-4-D with any required attachments to us at. Use this sample letter to dispute incorrect or inaccurate information that a business supplied to credit bureaus. Include any required attachments (e.g. ➢ Even though you are representing yourself, you MUST fill out this section. a. Type in 99500 in the Case Cross Reference Number box. b.