Notice to customer: require certified check or cash on next order

We thank you for your payment of $[AMOUNT, ex. 5,000.23] for [PRODUCT(S) / SERVICES(S), ex. your order for five Magnaflux compressors]. As you know, we greatly appreciate your business. Although your original check was returned due to insufficient funds, we understand your position; cash flow is indeed tight these days for all firms.

We wish to offer you the best service possible. For this reason, we will require a cash or certified checks payment on future order{s}. I'm certain you will find this reasonable, as our suppliers and creditors also hold us to strict terms. [MENTION LENGTH OF REQUIRED PRE-PAYMENT OR REVIEW PROCESS, ex. Since you have been a good customer, we will be glad to review your account in the next six months and offer you better credit terms.]

Sincerely,