Cancelling of Telkom contract

I have requested Telkom to cancel my sim card contract as it has expired long time, but to my surprise they still deduct every month. I have call the contact centre, went to their shop store, and always provide me with the false answers.

Please help me to cancel this contract as i have another three lines that are currently active with Telkom. The line that i want to cancel is *** FreeMe 1GB and my Account no ***.