@Banker  

You don't need to yell.  I was responding to @Dgreek who asked:

"I am deciding NOT to use recurring sales receipt with a particular customer going forward and I want to mark that as not paid. How do I do this?"

Indeed, you cannot mark a sales receipt as unpaid.  If a sales receipt is issued in QBO, it will record the transaction as though it has been paid.  If the payment gets declined, that's another issue and not what Dgreek was asking from what I gathered.