If you were late in making your payments and would like to apologize, here is a sample template you can use to write an apology letter for an overdue payment.
I am aware that I have yet to pay my monthly balance for my debt. I am sorry because I recently encountered some personal problems. A member of my family got ill and I had no choice but to spend a lot of money for his hospital bills. It is not something I wanted to do as I definitely planned to pay my remaining balance to you in time. I don’t want to be known as someone who can’t pay his bills on time.
I can assure you this won’t happen again. I attached my overdue payment and I guarantee I will pay the rest of the remaining balance on time.