Dear :

I am sorry to learn about the damage to the [product] that you purchased from us. We are certain that the damage occurred in shipment.

I've ordered an exact replacement from the factory and have been told that it will take [days/weeks] to get here. I'll call you as soon as the replacement arrives, and we will send it to you by express delivery.

Please accept our apology for the inconvenience this has caused you. I'll be in touch very soon.

Sincerely yours,

[name]

[title]