FNB and the ********** debit orders are at it again!

PATHETIC... I have been struggling to reverse a debit order for more than X2days. Their app keeps giving me an error saying the amount is too high. That time its an and odd R171. When asking for advise, after going through a couple of bankers, the last advise i received from them was I should contact the supplier. Like really, how do you contact ********** debit order people again. So what, i should call the ********** and ask them to stop debiting my account.... wheres the logic in that.