Contract cancelled - but charges continue.....grrr

I cancelled two contracts in approx Sept/October 2015. The one contract was cancelled and the last debit order came out of my account in November. In December i received a statement showing that the second contract was still being charged for on my account. So i called customer services to ask what went wrong. The customer services person then told me that the second contract was never cancelled on their side. I asked for a copy of recordings so i could prove that i cancelled both contracts simultaneously. The customer services manager was called and said he would handle it, which he didnt. Until today i wait for a response. So today i call Vodacom to check on the credit that was due as December debit included the contract that was cancelled already and the guy at cancellations keeps cutting me off! ***! I have a friend that worked in call centre and she has told me about the call centre agents and how they gipo it so that no one suspects a thing - they cut you off while they are speaking. Absolutely annoyed right now! Spoke to a man named Lungile and then he transferred me to the wrong department - then you have \brisley"who is customer care and speaks like she is falling aslp!"""