Telkom Cellphone Contract

I have been made aware by my bank that I have an outstanding amount from a cellphone contract from more than 5 years ago that I don’t know about. The original contract was messed by a consultant from the Clear Water branch that was meant to be sorted out, who admitted the mess up was on her side. Now my credit is messed up and have this account always reflecting on my credit record. The last time I spoke to a call centre agent 5 years ago and to this day has never been sorted and have never received any feedback from Telkom since. How is this still not sorted out and no communication sent out. I don’t have a cellphone contract with Telkom I requested all this to be sorted out years ago Why is debt still following me??