Not been professional

Hi my name is busisiwe Nkosi I have a problem with cell c I pay the money I was owing. But when I call the cell c to open my line they said they can't open .if I ask to cancel the data the lady I was talking with she said the contract it expired next year I know I didn't signed any contract about the data.now I pay 500 every month but they close the line I can't use the data I pay .if I want to cancel they refuse. What must I do. Since February I pay but I can't use any line .pls help