don't know they duties

I went to the cell c at the mall@reds to cancel my contract they advised that I should call and cancel I did that and was transfered from one department to the next eventually they said they said it will be cancelled when the contract expires now the contract is renewed without my knowledge and I'm charged more then I was paying this is totally unprofessional and wrong when I called to find out what's going on all they can say is that the contract is renewed and I'm liable to pay.I need someone to sort this out as I don't need this contract