Unpaid Invoice Demand Letter: Free Template & How to Send It (2026)
A client owes you money on a finished invoice and the polite reminders stopped working. An unpaid invoice demand letter is the dated, businesslike letter that names the invoice number, states what is owed and by when, creates a record a small claims judge can read, and often gets the bill paid before you ever file. Free template, certified-mail steps, and verified 2026 state small claims limits inside.