Re: STOP LATE PAYMENT CHARGES
Do you hope they will pay the bill? (Don't capitalize debtor statement.)
Two things. One, you are being very forgiving, but I don't think that's going to work. Two, it doesn't look like this one is going to pay the bill anytime soon.
If you write shorter sentences it will be easier to see the errors. Also, your sentences will be easier to understand.
I would be more straightforward. Perhaps:
Your bill is three months overdue. If the matter is not resolved soon it will have to be referred to a collection agency.
Not a professional teacher