Thank customer for order, apologize for delay and give estimated time of fulfillment.
1234, Main Street
Boston, MA 02123
08 April, 2005
<Recipient Address Goes Here>
Thank you for your recent order <reference to order> of <items ordered>. Unfortunately the <merchandise/items/products> you ordered <are/is> not available at this time. We currently have <them/it> back ordered and expect to have <them/it> available by <date>.
We apologize for any inconvenience we may have caused and will notify you as soon as we can fill your order. <Optional description of what can be shipped now.> Thank you for your patience.
encl: <List of enclosed items goes here>