How To Write A Formal Demand Letter For Payment And Money Owed To Clear Outstanding Debt? A demand letter is also called a debt collection letter.The court has placed the most commonly used forms on line as a resource. Please be advised that the forms detailed below are intended to be a guide. To start a case for money, the plaintiff fills out forms called a Summons and a Complaint, or a Summons with Notice. Use this letter to ask a customer to pay the money that they owe you. Put your business letterhead at the top of the letter. The Sheriff's Office can attempt to collect outstanding NYC Civil Court Judgments on your behalf. You'll receive an email within 24 hours explaining what documents are needed to complete your claim. Typically, we require: A copy of the death certificate.