2+ months later, unauthorized upgrade done on account still not resolved and account handed over to attorneys!

After being assured everything was sorted and cancelled, and receiving a statement with 0 balance, I called in this morning to doublecheck if all is in order after fraxxud was done on my account where an unauthorised upgrade was done in-house and I have been informed my account was handed over to legal because there is an amount owing. This will obviously affect my credit score. With an attempt to call customer care and a lot of transfers to different departments no one seems sure on how to rectify this as I owe Vodacom nothing. This is has been a draining and frustrating 2+ months of trying to sort this out, not forgetting the amount of time and airtime I have used to call. Please can someone get back to me asap.