We have appreciated your loyal patronage for these many years. We know it is because of excellent customers like you that we are in business. We are pleased to be associated with you.
After reviewing some files, I noticed you are (number) days past due on your...
Dear (recipient's name),
We have appreciated your loyal patronage for these many years. We know it is because of excellent customers like you that we are in business. We are pleased to be associated with you.
After reviewing some files, I noticed you are (number) days past due on your (company) bill. I'm sure this is an oversight. Please remit payment (company) to avoid any collection fees.
Again, we are grateful to serve you. Please feel free to give me a call if you have any questions about this bill.
Sincerely,
(your name)