Dear _________________

Your letter informing us that the ________________________ (missing item) for your new _______________ (product) was not included in the carton has been brought to my attention.

There is a package on its way to you now that includes the item and a little something extra. This is our way of saying how sorry we are for having slipped up, and thanking you for choosing the ________________________ (name of product).

If I can be of assistance to you in any way in the future, please call us at any time.