Over chargers on my sim card data contract each month

Am writing this as an unhappy client/customer of Telkom as I was requested to send proof of account that reflects that there was money in my account before the debit order date last month (june) which I was charged a fee for but then Sinenhlanhla( Telkom's consultant) explained to me that It will be substrate from this months payment (July 31) if really it happens that the was indeed money in the account and that has not happened, come to think of it this is a data sim card contract which I was/have to pay R200 every month but some time this year it start increasing every month and I've made a plea that this mustn't continue and I was promised it will not but am still experiencing such what is it expect of me because I called some many times and this kept on going and seems like it can't be resolved.

Thank you Obakeng Motileng