DearThank you for your letter of   [date]   in which you informed us that  [product]  you purchased was [nature of problem].We are sorry that you experienced this problem and are enclosing [nature of compensation].  While we make every attempt to insure that our products are [address complaint]， this unfortunate incident can occasionally occur.We are very appreciative that you have taken the time to bring this to our attention and would like to thank you for purchasing our products