A complaint letter is a written correspondence addressed to a company, organization, or individual expressing dissatisfaction or concern about a product, service, or situation. The purpose of a complaint letter is to inform the recipient of the issue and to request a resolution or action to rectify the problem.

A well-written complaint letter should include details of the issue, such as the date and location of the incident, names of individuals involved, and any relevant documentation. It should also clearly state the desired outcome or solution to the problem.

Complaint letters can be sent via mail, email, or through an online form provided by the company or organization. It is important to maintain a professional tone and to avoid making personal attacks or using inappropriate language.