NEDBANK ARE A BUNCH OF *******

I made an arrangement with Nedbank for my personal loan account. The arrangement was that they debit R100 every 26th day of each month until I finish paying them. On the 22nd of September 2017 one of their collection consultants phone me to remind me that they will be debiting R100 on the 26th of September, I told her to debit R200 instead so I can quickly finish paying them. On the 26th September 2017(tuesday) they took R2312.72 from my account. When I called them the same day, the lady(her name is Busisiwe) told me that the money was not yet showing on their side. I called them again on Wednesday 27th and spoke to a lady called Londiwe, they still didn't help me. I'm now unable to make payment for my car and other accounts because of the inconvenience that was caused by them. They are sending me from pillar to post, telling me that it takes about seven days to get your refund. This was their fault and now they are telling me about the stupid seven days, really? the money should be transferred from them(Nedbank) to my account(also Nedbank) why the hell should it take seven days? I'm so furious because they did the same thing to me last month. This is no error, but something that was done deliberately. You can't have the same mistake twice in two months consecutively. They are really ********* taking advantage of people.