The letter must outline your complaint, the harm you suffered, and how you want the problem resolved. This is called a 30 Day Demand Letter.We've put together some of the most common questions about your auto insurance claims. This letter outlines your claim and provides information that might not appear in your medical records. The affidavit requests the negligent driver to identify all of his or her vehicles and whether any potential family members have insurance coverage. You must sign the form. The "Final Settlement Detail" document can be used to fill in the above information. Tell them you need a Massachusetts Registration and Title Application (RTA) filled out with their electronic stamp on it. If you wish, you may use the City's claim form. Demand Letters in Personal Injury.