HOW SAFE IS YOU MONEY WITH FNB?? SAME UNKNOWN DEBIT 3RD TIME

So the saga Continues. Once again the the unknow debit of R8199.00 was debited This is now the 3rd time. Previously the card was stopped and a new card was issued. I requested a stop payment twice at FNB. I called FNB and was informed that I need to complete a Dispute form and fax back to them. Seriously now my account is overdrawn and FNB will start charging R120.00 overlimit fee again. I DID NOT AUTHORIZE THIS DEBIT ORDER HOW MANY TIME MUST I BEG FNB FOR ASSISTANCE.