Cell C contracts - FRUSTRATING service!

I had a data contract with Cell C that was due to be cancelled on the 24th of August. Due to previous experience with them and cancellations of contracts after 24months, I raised the cancellation request in May and also the subsequent months to remind them to not renew but to cancel the contract. I called them last week after I noticed that the line was still active, after which they apologized and confirmed it would be fixed by the following day and they would contact me. Needless to say nobody called, and today I got the statement for September for this account. I am EXTREMELY frustrated, this is the second time this is happening with CELL C, and I need this resolved now I cannot keep paying for your mistakes or failure to cancel contracts on your systems!