FNB customer service is disappointing

It brings great disappointment that a bank that I have been using for more than a decade, has let me down with zero assistance, an amount of R 1317,25 was debited from my account after by rain network, There’s no paperwork permitting this debit, it’s a prepaid service that I have always paid for it whenever I needed it, I have reported this issue to FNB and my concerns fell on deaf ears! I was told to deal with rain network as the merchant , rain does not have an office! They don’t have a walk in centre ! They don’t have a call centre! I have escalated them as well, however I am deeply disappointed to the service I received from FNB!