Here's a sample to help you write a complaint letter about a product or service. File a written complaint with the DPU.Consumer Action offers a sample complaint letter and an email complaint template. You can cut and paste these documents below. Contact the Division at (801) 530-6601 during normal business hours. Be clear and concise. Describe the item or service you bought and the problem. The userfriendly portal serves as a centralized hub for residents to submit consumerrelated complaints and empowers residents to actively participate. First of all, you should write your complaint in details, and in good language. Find out how to craft a formal complaint letter.