FNB Customer Service is Horrific

I was in arrears on my credit card by R 8000 on the 01 May 2019 due to unemployment. The due date for payment was the 07 May. I paid the arrears amount on the 11 May 2019. The status was changed to Pre-Legal on the 12th May 2019. I emailed pre legal and asked the representative via email whether there would be a normal debit order on this account or whether a payment arrangement would be needed. A payment arrangement of R 800 a month was entered into until such time as I obtained employment and am able to settle or pay more into the account. Suddenly a debit order of R 5600 was then taken from my account on the 31st of May and then again on the 05 June another debit was of R 660 was debited from my account. I sent a total of 8 emails over the last 10 days to pre legal asking for help phoning incessantly for someone to please help me with this query and refund this amount as I have no money left for this month. Pre-legal department just says sorry there is nothing they can do. My debt to FNB is R 30 000 surely it is ******* to debit nearly R7000 off a R 30 000 debt? The ladies at pre-legal are arrogant and abhorrent to interact with, they are belittling and only want to get the money from you. When a person is down and out and trying to repay their debts and still get belittled is more than embarrassing it is indignant. When I ask the representatives to please escalate the refund they say their managers are in meetings and doubt whether they will be able to get to my query. They say to me that with the interest I owe there is nothing they can do to refund that money and wont even look into the matter. How can a credit provider debit more than 10% ? It is not *******? FNB has in effect debited close on R 7000 off a R30 000 debt? This is not ok and the way I have been treated by the pre-legal department is abhorrent when I in good faith am trying to repay the money and in good faith repaid the arrears (yet was debited nearly the same as the arrears). I have nothing left to live on for the rest of the month. I have emailed care@fnb to no avail. I have sent 8 emails to prelegal over 10 days not one has been answered.