Telkom Stole My Money and will not refund it!?!

I cancelled a contract with Telkom, gave them ample notice on 24th Novemeber 2016 to be cancelled by end of December 2016. In January 2017 I was again charged for the January contract and a portion of it charged in February 2017 too. I stopped using the service at the end of 2016. They have no proof of me using any data after the 31st of December 2016. It is now 7 months later and up until today the R824.00 they ripped me off with remains with Telkom. I have phoned the call centre repeatedly, and I mean dozens of times. I have e-mailed many people many many times, I have been to the Telkom Centurion Branch twice. It is of no use! They are useless in every sense of the word. I want to stop doing business with Telkom permanently. We have actually completely cancelled Telkom at our dealership due to the same terrible service. Enough is enough Telkom, I want my money back and I am not going to let this one go. I am reporting this for the second time on Hello Peter as I was again not refunded on the first complaint I put here.