Click below to submit documents for an existing claim. 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. Learn how to fill out a Financial Statement Form, which you need for many types of cases in Massachusetts Probate and Family Court. You have two options to submit your claim form and additional documentation. Mail in your documentation to the following address: Office of the State Treasurer. I found some money on FindMassMoney. No indication of this on the envelope. To begin your search for unclaimed funds, enter a Last Name or Business Name. Either a Last Name or Business Name OR a Property ID is required.