Dear :

We have received your letter of [date] in which you complained about the delayed delivery of your order.

I'm sorry that we have not been able to deliver your shipment as scheduled. The delay was caused by . I expect that the problem will soon be resolved and that we will be able to deliver your shipment within the next days.

I will notify you as soon as the shipment is ready for delivery.

Sincerely yours,

[name]

[title]