INEFFICIENT SERVICE

My contract with Cell C ended on 22 December 2019. I notified their customer service, via email that I would be porting my number to prepaid once the contract has ended. My last payment on the contract was on the 27 January 2020. Cell C has continued to bill me - although it indicates that the number is pre-paid. I have, since FEBRUARY 2020 BEEN REPORTING THE MATTER TO THEM, AND TO DATE THEY HAVE NOT SOLVED THEIR INCORRECT BILLING AND THIS HAS AFFECTED MY CREDIT RATING AND I AM NOW NOT ABLE TO GET ANOTHER CELLPHONE CONTRACT!! I AM TIRED OF PHONING IN TO THEIR CALL CENTER ONLY TO BE ADDRESSED BY INEFFICIENT, DUMB OPERATORS WHO DON'T KNOW THEIR **** FROM THEIR ELBOW. FOR ALMOST A YEAR THEY HAVE NOT BEEN ABLE TO FIX MY ACCOUNT AND I HAVE A BLACK NAME. ALL RELEVANT DOCUMENTATION IS AVAILABLE FOR PERUSAL.