To whom it may concern,
I am writing this letter in reference to my recent visit to your establishment.
Normally, I'm a very easygoing person and not one to send a letter like this, but the quality of service I received was highly unacceptable. Consequently, I would very much like to be reimbursed for the money I spent while patronizing your business. A customer should not have to pay for service that is so far below reasonable expectations.
Please find my receipt attached. You can send reimbursement to the above address. I thought it best you know the problems inherent in your establishment so that you can deal with them.
Thank you very much.