CAN'T REVERSE UN KNOWN DEBIT ORDER-FNB REFUSES.

FNB does not want to reverse a debit order that I'm not aware of, a debit order from Clientele *** for an amount of R294 was debited, I contacted FNB and they told me they can't help , I must contact service provide which I don't even have their contact details. Why is FNB doing this? are they working with these "service providers" to ***** us of our hard earned money? Why must I keep losing money to debit orders that I don't know? I have been a loyal FNB customer since 2003 but the service I'm receiving from them is terrible.