Double payment

I have a loan with African Bank, on the 22nd I called their head office to change my banking details. I spoke to a lady who told me that they would not be able to debit this month's installment as per normal as I was getting paid the following day. We then agreed that I would go and pay at one of their branches as already a debit order was lodged with my previous bank. I went and paid on the 23rd and on the 24th my money was debited from my account. Which now means I paid double this month. Yesterday I called to request a refund and I hear different stories every call I make. I need this money as I have not fulfilled all my monthly obligations and now I am told that it is difficult for African Bank to give refunds. If your consultant hadn't given me the option to go pay and the branch and wait for the debit order to run I would have. This is frastrating and very unprofessional of this bank