Very rude customer care agent named Mbali

So I made an online payment to normal telkom monthly payments. I made the payment 5 days before the debit order date. Mind you its their system made to make payments, so on the date of the debit they tried to make a debit but I had removed my money cos I had already paid all my orders. So apparently the rejection fee should be paid by me, but why me it's their online payment system if I wish to pay why should I pay rejection fee if I had already paid. I tried their agents one of them called Mbali, she was very rude, she didn't care about customer service. I'm canceling my contract with them. They act like their are doing us favours.