Cell C.....poor service

Constant bad service, constantly being harassed for arrears pmnts. I have suitted proof of payment to multiple agents, multiple numbers, multiple emails...account not rectified. Then, without authorisation a debit order was processed. I made manual pmnts every month, on time. There can be no arrears as I have proof of pmnt. Why can't I be assisted in having this issue resolved. I cannot make more payments as I owe nothing. I expect this to be resolved, the service is horrible and I do not appreciate the way I am treated