Vodacom data contract cancelled but being billed for

I cancelled a data contract in July. I have been billed for this contract for the past two months. I have made numerous amounts of calls with non existent customer care nor service. Even escalating your query does not make any difference. Then I get an sms on 3 October to tell me that my request to convert the data contract number to prepaid has been activated which I have not requested. ???? I don’t know where to turn to next to get my query resolved.