This is to acknowledge the receipt of your letter of (date), in which you informed us that the merchandise delivered to you on (date) was defective.
If you will read our terms and conditions for sale, you will note that our policy provides our clients with (time) to inspect and either accept or reject our merchandise in regards to defects, in as much as we feel this affords our clients an adequate period of time to be assured that the merchandise is free from defects. Since this is the first time you have made this request of us, we will assent the return of the merchandise and issue a credit to your account in the amount of $__. Please (instructions for return of merchandise).
We would like to apologize and say sorry that you experienced a problem with our product and appreciate having your firm as one of our valued clients. Once again we would like to say sorry for the inconvenience caused to you and your company.