Dear Sir,
In deference to your valuable time, I would like to express our apology in the matter of merchandise shipped to you.
We are aware that your purchase order clearly stated 45 cases, while we erroneously sent you the shipment of 65 cases. Meanwhile, there are two options available at this time; you can keep the additional merchandise and we will bill you thirty days from now, or we will arrange to have it picked up at your
loading dock and issue a credit to you. Please let us know of your preference.
We will do everything in our power to ensure that this type of error does not occur again. We are grateful to you for your understanding. If ever we can be of any assistance in any way, please do not hesitate to call on us.
Thanking you
Yours truly,
Your Name