Early contract cancelation dispute

I asked for an early contract cancelation settlement in May 2023 and I went to a vodacom outlet and paid. I received an email that my number was successfully changed to prepaid, to my surprise Months later I'm called by lawyers that I'm owing Vodacom and after several attempts to call vodacom and go to a vodacom store no one can explain how I'm owing them,when I settled the account in full and my contract changed to prepaid successfully. I'm even more angry that this is now affecting my credit score and ruining my life after they went and updated a closed account that I have defaulted payments. Vodacom please fix this,it's not the first time I'm fighting for my rights as a customer when it comes to you. I have every right to cancel a contract earlier when I have funds to do so