Expired / Lapsed contract cancellation

I’m not happy with Telkom Mobile service. I had data contacts with Telkom mobile, and it expired on the 22 September 2017. On the 14th of September I give them my notice not to renew this contract. I send the forms the same day I put the notice. NOTHING happened. You guys didn’t do anything, why? I don’t know. I went to the Telkom mobile Southgate branch on the 12 October 2017, I filled the same forms (I already sent to them), and again nothing is done until now. The call centre is also not helping. What must I do for you to cancel this expired contract? 24 months has lapse so I don’t want this contract to continue. This service off your sucks. I wonder if its only me having the same problem with Telkom mobile. you keep on debiting my account, which I don't understand why.