Reply apology and notice of shipment in replacement

Your letter of [date] has been received, and we were very
sorry to hear about the problem you experienced with our
[product].

We maintain rigid inspection standards, but occasionally
an imperfection does slip by, as it unfortunately did in the
case of your [product].

We have entered a replacement order to be shipped to you
at once. Your satisfaction is extremely important to us and
we apologize for the inconvenience you have been caused.

Thank you for purchasing our products.

Very truly yours,