Gentlemen:
This is to acknowledge our receipt of your invoice ____________
A check of our records indicates that payment for this invoice was made on _____________ (date) with our check payable to you in the amount of ___________.
Please review your records and bank deposits to be sure that you have not received our payment. If you are still unable to find a record of payment, let me know, and I will request a photocopy of our check, and forward it to your office. This normally takes about ___________ (period).
If I do not hear from you, I will assume that you have found our payment and have appropriately credited our account.