I am sorry to report that your check number #______________ in the amount of $______________ has been returned to us by the bank for insufficient funds.
This may be the result of a simple error. However, we must insist that you replace the insufficient funds check immediately, and in no event later than __________, 20____ . Therefore, please bring or send to our office [a certified check], [replacement check] in the amount of $__________ plus $ to cover the insufficient funds charge assessed to our account by our bank due to this matter.
If you have any questions, please feel free to call the undersigned at (____) _____________.