After paymnet arrangmnet made they still take what

A payment arrangement was made with there attorneys Brooks and Luyt, after months of paying the arranged amount I see on my back cheque account a debit order of R 3620.00 taken, I phone FNB and the card division tells me it was a instruction from the attorneys to do this and it not there fault, I phone the attorneys and they tell me its not them but FNB, and that until the money is actually reflecting in the credit account that can tell FNB to pay it back to my cheque account, I find this extremely hard to believe as both accounts are with FNB and the one department phones the other one sees that the money has been removed and then refunds it from there side, I got into issues because I lost my job awhile ago but I have not walked away from any of my responsibility's I made arrangements, who gives anyone the right to deduct what they want from a account with the account holders permission, FNB I want the order reversed and paid back today, Thank you