Telkom **********ly taking more money from my acc

I had a 2 year LTE data contract which ended in 2020. Telkom phoned me to extend the contract paying R199 which I did. Now all of a sudden that my contract is supposed to end I'm paying more that R199 and these are costs I'm not aware of. The latest debit from my account was R350 and that month end I will pay R900. This is a **** and I feel ******. Why am I paying more than what we agreed on? I complained and they said that the mistake was on their side but they still expect me to pay???? Please sort out this mess your consultants made? I will be taking this further if not resolved.