FNB unauthorised debt orders... they will not refund?????

So... I voluntary give back my credit card to FNB... and make a payment plan with them to settle. This will take 5 or so years. Since January 2018... the correct amount gets debited from my cheque account. Then suddenly this month August 2018... I get debited twice. A simple phone call to credit card division. .. and a nice lady reverses the full amount back to my cheque account while on the phone with her... simple and professional. All fine... but a few days later... I get debited again. So I call in again. This time, I get told they can't reverse the debit order... and I will have to wait 3 to 5 working days for my money. Very inconvenience as my bond payment was due the next day. When asked why it can't be refunded like it was done just two days ago? I get told they don't know how that lady did it...ummmmm. .. really. Asked to speak to someone higher up... and they just put you back to the phone prompt. After speaking to at least 10 different people.. maybe more... I go see my bank manager. And she can't do anything either. So I decided to just wait for my money. 5 days come and go... no deposit. So I call in again. I now get told... they can't give my money back? So I go back to you bank manager. .. she gives me an email ********** so I write a long email about my frustration. .. that was yesterday morning. Still no reply... and no one seems to be bothered. What on earth is going on.... my money is mine... not for FNB to just do as they please. And sounds like training is useless if one person can do a reversal for an unauthorised debit order, and the next person. .. well persons can not? All I want is my money back? My money. I'm angry... frustrated and damn right disgusted with the lack of professionalism at FNB.