Struggling to cancel contract

Upon my 24 months contract ending, I call Vodacom to cancel my contract on April 2021 and I was informed that I had to give them a 30 days notice for cancellation of the contract. In May 2021, I called again to confirm the cancellation and unfortunately, this never happened as I was notified that my account is in Areas and my account is going to be taken to credit collectors. In March 2022 I called them again and I was taken through a long process, being transferred from department to department. In the end, they went through their call records to verify if I really did record, and mind you that time I'm already getting annoying calls from the collectors.

07 March 2023, called them again and they still took me through the same hustle of transferring me to different departments and promised to sort out the matter in 24 hours but this still hasn't happened. This is very unprofessional and tiring. After long calls, they promise to send a confirmation email but that never happens again. To my surprise, the other lady from the cancellation department told me that I need to pay a cancellation fee as my number reflects that I had a new contract with them which I was not even aware of.