Telkom refuses to review my issue and my Credit Score is being affected.

in 2021 I upgraded my Telkom contract, the phone was never delivered but they kept billing me. After 12 months of no help from Telkom I investigated and found the delivery note had the wrong address and ID number. since then I've had 4 debt collection agencies chasing me for payment on an account I had reported twice a month for 2 years.

I don't know what to do.