Very bad service and very bad product

I am utterly disgusted by Cell C. I had a contract with them in 2019 to 2021.when the contract ended it became a month to month contract where they would deduct at the beginning and at the end of the month, me trying for months on end to cancel it, eventually at the end of September/October of 2021 I got it canceled and even then the consultant that had helped me said I do not owe cell c a cent. And when I did a credit check on my number I was hit with a WRITTEN OFF of R500 rand and when I called cell c asking as to why and could they explain it to me they said no because it was at a different department and when I called this number they had given me, there has never been an answer. Now I am left with a bad credit record due to cell c. And still not received a reason as to way I am owing something I have no idea about.