Standard Bank are *******!!

I have been double debited this month for a loan. Called customer care twice and spoke with a consultant who was very unprofessional. She blatantly advised me that they cant reverse the debit and I have to go to a branch. So I went to the branch only to be told that they also cannot assist. No one wants to tell me why I was double debited and how to rectify this. I have 4 more debits that need to go off for this month which will now be returned because of your error and I'm the one who now has to pay for the returned debit fee. This is now going to negatively affect my credit record and I want this rectified immediately. All I'm asking for is to return the money that was *******ly debited from my account.