Unhappy Customer - NEDBANK

Nedbank has debited my Credit Card account for the full outstanding amount without my permission, i called to inquire on a reason twice, and on my second phone call to your call centre (dated: 10/07/2019 - Time: 11:35pm) i had requested the lady to amend the debit order amount to the minimum and i had requested for the team leader on duty to give me a call back - which was not done. Today Nedbank has debited my account for the full amount again. i don't understand? i am not in arrears of any sort. A recorded telephone conversation was done and agreed, so what is going on Nedbank? why all of a sudden a system change without notification? A decent courtesy call is customer service.