Cell C pathetic service

I had a contract with Cell C, which I cancelled in August or Septemeber last year 2018...to date it still appears on my credit report and I've tried numerous times calling the contracts cancellations department only to either be put on hold for over an hour at a time just to be redirected to their legal department and be put on hold for over a half an hour again...for some reason no one has answers or can send me proof that my contract has been cancelled...its been over 10 times that I called in...I went to the Secunda branch all they do is give me the same number to call and upon my last attempt last week I was told the head office is on strike and apperantly no one can help me. This is why I canceled the contract in the first place you can never get quick and effcient service ...they good to sign you up but cant help you after that Please can someone urgently get back to me from Cell C with a cancellation letter as this is affecting my credit scoring and in future if people cancel a service update the credit beurue accordingly so we dont have to run around doing your job for you!! K SANDIAH