Dear
　　It is because we do not want you to experience unnecessary embarrassment， that we are writing this letter to you.
　　As we have reminded you， your account is past due and I am sorry to inform you that if you were to present your charge card at our store today， our sales personnel could not accept the charge without an okay from the credit department.  This would necessitate your going to the credit department to discuss the status of your bill before the charge would be approved.
　　You have been too good of a customer in the past to have to go through this procedure， but unless we receive your payment we have no other alternative， due to our company policy.
　　We have enclosed a self-addressed envelope for your convenience and are requesting that you please mail us your payment today.  Thank you for your anticipated cooperation.