This letter praises a company for providing a refund when asked.
1234, Main Street
Boston, MA 02123
<Recipient Address Goes Here>
It's very common for a company to offer a "full refund if you're not satisfied." Unfortunately, it's less common to actually have that company follow through and issue a refund when the need arises. I'm writing to thank you for refunding the <$amount> I spent on <product or service>.
I may have been unhappy with <product or service>, but I was very impressed with <company name>'s willingness to stand by its offer. Thank you very much for your courtesy and service.
encl: <List of enclosed items goes here>