Unable to cancel contract

I cancelled my contract at the end of May, but to date I am still getting charged. I call every month to query and all they can do is "escalate" the query. I am asked to do the same thing every month, i.e.resend the original email, but I continue to be billed. When I ask to speak to management, I am told the team leader is unavailable. I even emailed the team leader on one occasion and to date have not received a response. The cancellations department is unreachable, there is no way to contact them. I have even sought assistance at the Telkom store. All they did was emailed the cancellations department. I am fed up.