Payment arrangement and incorrect debit deduction reversal

I had a loan with FNB, lost my job this year in February and then i sent my documents to them for the insurance claim. They paid for my loan for about 6 months, which i am grateful for. I kept updating them about my unemployment state until mid October. I then got a job in the very same month and by then my loan was three months behind with payments(R4550). I got my salary and then they deducted the money i was in arrears for and got in my account again and deducted the same amount for the second time(totaling R9200). I called them and asked them to reverse the extra R4550 they deducted and to also make an arrangement , to have my arrears split for few months(deduct monthly installment plus a certain extra amount to cover for the arrears) then they told me they can't. I am very dissapointed because i am not denying to pay my loan but instead requesting them to assist me as i don't owe only them and need to cover the other creditors as well but their response is senseless. They told me they can't reverse the extra deduction as it is not reflecting on their loans department but the lady told me she can see it on my statement that it was deducted and that i must wait until it shows on their side which she doesn't know when that will be. I want my money 'cause now i am left with nothing in my account. And no one called me to even apologies or at least send an sms to say they acknowledge and apologize for the inconvenience they have caused. I have been a very loyal customer for FNB since 2006 and this is the thank you i get? I will never ever recommend anyone to FNB, NEVER!!!