Unhappy client

Vodacom- Reward Department-Ref number (FRC010108) I have a call from Sales lady she convince me to buy Data. I told her I have two contract with them am not willing to pay more that R500.00.The sales lady promise me the amount will be R500.00 plus something. I agree to take the promotion , I have lost my job. On the 22 September 2020 I receive a msg saying they will debit R795.00.I went o Midrand branch Vodacom to enquire. I have made many calls and spoke to Supervisor Shannon. She promise me and give me the above ref number they are investigating the matter. Yesterday I say a debit ofR795.00 without conclusion. Can you please assist on the above matter.