Worst Service EVER

Received a settlement letter from my creditors stating that the account has been paid which means NDA also knows about it. I received the letter way before my debit order date with NDA but they still took the amount they have been taking which is totally wrong as they needed to take only one amount. This all happened in September and in October they needed to debit one amount to be paid to my creditor which should be the last amount. I contacted them to find why did they take the full amount, no could explain as why the full amount was debited in Sep and Oct yet ive got only one creditor to pay. I was assisted by an agent (Rowham Coetzee) who hasnt got back to me to discuss a way forward