Terrible Service

Telkom mobile have placed a missed payment on my credit report, I had a contract with them back in 2013, the account was written of as I was retrenched at the time. It is now 2021 and Telkom mobile has raised this on my credit report without even consulting me and without any payment agreement of any sort in place....I have tried to contact their accounts division, I was told turnaround time for a call back I 24 hours...I have tried contacting them thrice and still no call back. I have contacted VVM legal division which handles Telkom mobile collections and they say I don't have an active collection standing with them....Can someone from Telkom mobile accounts contact me urgently....***....I need this resolved asap