[Your Name, & Address here]
[Recipient Name & address here]
We acknowledge the receipt of the promissory note sent by you, dated [date].
We want payment against the due balance of principal and accumulated interest in the amount of $[total amount].
We look forward to receive the full payment by [deadline]. In case you cannot make the payment before this date, please inform us immediately.
Thank you for your prompt attention regarding this matter.
Encl: [Enclosures List here]