Signed contract without my consent

A contract was signed under my name without my consent.I have been going back and forth with MTN for years now and this is ruining my credit score.In stead of upgrading a router package I had in 2021 the consultant added a second contract.I am not getting any assistance from MTN stores as well as emails.Everyday when you call a different consultant attends to the case and you have to start over again.This is currently reflecting as unpaid debit orders on my side and it’s so frustrating.