Abuse of power. Unauthorized debit orders!

I am still being charged more than triple what I signed contract for. Telkom keeps on adding data bundles to my account which I did not ask for, don`t use and cannot afford. I have been in the Stellenbosch Telkom office three times in March only and several times every month since my contract has started. Each month they tell me that the problem is solved and that the mistake will not happen again, but every month I pay way to much on my account because the problem goes get solved properly. I am really disappointed that I have to complain for the second time this year in this platform about the same company and about the same problem. I am being treated unfair and ********ly. Telkom is misusing their ability and power to take whatever they want from my bank account via debit order.