Blacklisted

In 2021 I had an upgrade with CellC. 3 different SIM cards where sent to on different dates. I called their call center and I was told to destroy 2 and keep the one I need. 2022 got an email saying I owe cellc R530 and account has been handed over. I asked why waited for a full year. I have also provided communication that it was Cellc error for sending me 3 different sim cards. No one wants to listen to me and blacklist me. This is not right. I want my name.be cleared from credit bureau