3. Inform customer of the outcome of the complaint. Three days later you are advised that you may not refund the customer's money, but you can offer them another workshop free of charge and/or they can have a one-off one-on-one session with a consultant. Write a formal letter advising the customer of the outcome of the complaint. Use the Customer Complaint Outcome Letter Template to guide your work. This letter is an opportunity to demonstrate high quality customer service, so write the letter with this as a goal