Vodacom is truly disappointing

I genuinely cant believe Vodacom. my Contract ended in November 2023 yet I still had to make payment in December 2023. I was then told I had to call them to get that contract cancelled, I did that and they assured me my account was converted into prepaid and all was good. Now months later I get a call from VVM saying that my account has been handed over to them and that I owe Vodacom. Hoooowww? I'm so disappointed, now I cant get through to them, tried to get help from Vodacom twitter and still this isn't helping. :(