Canceling Sim contract and penalty.

I was offered 20g instead of the 2g I am currently using an turned out it was for a new Sim contract. After seeing the billed invoice on first week of March I contacted vodacom an after long conversation with consultant an options I opted to cancel my 2g Sim contract cause it expires end of March 2020. Vodacom decided to cancel the 20g simcontract instead an bill me R9720 for cancelation fee. When I queried this amount I was informed that it will take 14 to 21 days to resolve my query. I have not received any feedback from vodacom after 2 days of the query an still waiting for a resolution. Worst service ever.