Dear Ms. Elena,
I was sorry to learn from your letter of 18 August that a mistake occurred in dealing with your order.
This mistake is entirely our own and we apologize for the inconvenience it is causing you. This occurred because of staff shortage during this unusually busy season and also the fact that these 2 books by Lawrence have identical bindings.
12 copies of the correct title have been dispatched by parcel post today.
Your account will be credited with the invoiced value of the books and cost of return postage. Our credit note is enclosed.
We apologize again for this mistake.