Contract cancellation

One of the vodacom agent called me , and offered me a contract upgrade, but later I found out that she **** to me, I called Vodacom asking them to cancel my contract as I was **** to, they didn't do it, they are forcing me continue with the contract even though I told them I don't want it anymore, they are now claiming that I am owing them, I am really disappointed with vodacom, I will never ever enter into a contract with them