Gross incompetence from Cell C

Cell C's gross incompetence has resulted in me being handed over and getting a bad credit rating. My Cell C account is paid in full and on time every month. Cell C changed to a different system and my last four months payments were not allocated to my account. I have been in contact with Cell C telephonically and via email - Anele Shezi, Denver Naidoo, Zodwa Seloane. The debt collectors have subsequently sent me a second message regarding non payment. This is completely unacceptable and I'm not getting anywhere with Cell C.