Your account has been referred to me with instructions that I make final demand for payment of this debt.
Inasmuch as the outstanding balance is sizable, I have outlined a payment plan for you as a method to retire the entire balance over the next [number] months if you are unable to forward the full amount at this time.
Amount Due $
Payment $ Monthly
Due Date $
This offer is being made to you as our expression of wanting to settle your account in an amicable manner.
If we do not receive your first payment by the date indicated above, we will have no choice but to refer your account to a collection agency. We do not wish to take any action which might impair your credit rating and therefore request that you give this matter your most immediate attention.