Contract does not want to end

I had a contract with Vodacom in 2012 which I couldn't cancel during all this period so I had to wait for it to be finished which was 31 January 2015. The consultant who called me never told me I won't be able to cancel it after a month of having that contract. I was hoping it will be cancelled when the contract ends but they continued to take money from my account even though the contract has ended. So I need to know where do they get the permission to continue taking money even though the contract has ended and I never told them to renew it. With so many customers don't they get enough of taking people's money. I couldn't cancel this account for so many years being patient hoping for January 2015 to come and now they do not want to cancel this contract. When I call the Vodacom, they tell me to call other numbers to cancel and I don't have that time of running around calling people who won't help. When they gave me this contract, they called me but now I have to struggle trying to cancel an expired contract that keeps taking my money. I hate this, I really do!!!!