Here's a sample to help you write a complaint letter about a product or service. Complaint Information.Please explain your complaint: Try to be brief, but be sure to tell WHAT happened, WHEN it happened and WHERE it happened. Sample Forms These sample forms may be useful when filing documents for the civil and family courts. If you have any questions, consult an attorney. Complainants must detail their allegations on the Department's complaint form. 1. Fill out a Complaint form. a. Near the top of the first page, write your name in the space above the word "Plaintiff". To submit a complaint form, complete the complaint form and be sure to include as much information as possible. Developed were collected.