Renewing Contract Without My Consent

I finished my contract with vodacom before the renewal time. When the renewal date came, I did not know because I did not wanted to renew. I then went on my vodapay app to buy some data, and suddenly saw that I owe vodacom an instalment on my contract that I finished long time ago. I phoned the customer care and asked them about it and they could not answer me, they advised me to open a query and gave me a query number. They did not phone me or get back to me in anyway…a few days later a consultant phoned me from vodacom and asked me if i am aware that i owe vodacom…i told him that vodacom was not even aware that i owe them, i am the one who put in a query of the billing that i did not even know of. I asked the consultant to explain to me when was my last payment before they have realised that i owe them. He could not answer telling me that “Vodacom” said he must phone me, as if he is not working for Vodacom. I then asked him when did my contract start and when was it supposed to end, he stil could not give me an answer. I now get threatening sms’ to tel me that my phone will be switched off if i dont make a payment. Since i spoke to the two consultants one that made me put in a query and the other that told me that im owing until today no vodacom consultant has phoned me and explained to me what is going on. No vodacom consultant has phoned me and answered the questions that i have. I explained to both consultants that “I WILL NOT PAY THE MONEY THAT I DONT KNOW WHERE IT IS COMING FROM” on recorded calls.