Determine Your Scope
The scope of a complaint letter should encompass the relevant information necessary to resolve a problem, correct an error or repair a defect. It should provide the reader with exact descriptions, including dates, times and places. It should reference purchase orders, invoice numbers, payment records and even dollar amounts when appropriate.
In the body of the sample complaint letter the writer politely expresses dissatisfaction that a problem's promised resolution is long overdue. He supports his claim with facts.