VODACOM FAILED TO CANCEL MY CONTRACT AND THEY SENT IT TO COLLECTIONS WITHOUT MY KNOWLEDGE

My contract ended November 2019. I called Vodacom to cancel in December 2019. They said my account was on their old system and one of their consultants/Agents will call me back, they never did. I called again in February 2020 to cancel my contract, the lady I spoke to cancelled and confirmed that my account is cancelled and said I will have to pay for March. March 2020 Vodacom debited my account. April 2020, Vodacom debits again, I reversed the debit as I know my account has been cancelled. May 2020 Vodacom didn't debit, I figured they realized that my account was cancelled and that they debited by mistake. They haven't debit since then. No communication from Vodacom since that time. Comes March 2021, I receive and sms from Vodacom collections that I owe them???. To my shock, I call Vodacom that my account was cancelled last year Feb 2020. Vodacom collections said I should log a cancellation dispute with Vodacom. I did that, Vodacom say my account has been sent to collections therefore they don't have full access to my account but they have sent an email to administratiOn to log a complaint regarding failure to cancel my account last year. They said administratiOn will call me within 3 to 7 days, they didn't call me. I followed up , still no assistance, they said they will follow up with AdministratiOn and administratiOn should call me and I should give it a day or two. Still Vodacom didn't call me back. I don't know how to resolve this as my name will be tarnished because Vodacom failed to cancel my contract when I called in Feb 2020. They told me that administratiOn will listen to the recordings on the days I called to cancel my account and they will call me back. It's April now and I have been waiting... this makes me very upset. I am not happy with Vodacom customer service.