Days accrued for late payment calculation.

edit

I have a start date for when the payment is due that is calculated, so it is not in text format. I enter the date the payment was deposited (in text format). If the paid date is more than 5 days past the due date I need to apply a late fee, and deduct that amount from the deposited amount.

I have spent two days trying to accomplish this simple task. my Excel experiance has not been much help. Can someone pleas give me a hand.