Making Payments But Still Being Charged

I have been making payments to Telkom mobile and still getting charged for payment rejection fees of R200 because the system cant be changed according to your agents, I have called to sort this out and they cannot assist me, the manager wont speak to me and advised what the agent told me is what they can do, I believe this blatantly robbing me that I have to pay R200 extra a month.

I need to speak to someone higher than an agent who knows whats going on and able to assist me, else I will not be paying my contract and you cancel my services and will not get anything out from me.