Dear

We received your order for [item and number] and wish to
thank you.

This item is presently back-ordered and we are unable to
send it to you immediately. If, due to this unfortunate
delay, you would like to cancel your order, please send us
a note to that effect. Otherwise, you can expect delivery
in approximately [time].

Please accept our apology for this delay.



Try Google Search to find what you are looking for!

Here is some random sample letters.