Vodacom refusing to cancel my contract which ended in 2020!

Vodacom's service is really the worst. I would never recommend them to anyone. My contract ended in 2020 and I've still been paying and receiving my monthly top up airtime (which is fine) but in January I cancel this monthly airtime and switched solely to prepaid. But now in March I received a statement and find out that the agent I spoke to in January never cancelled my contract! So I call in again 2 weeks ago to cancel it, they then open up a ticket and escalate to a manager. I was then told by the agent that I'd receive an sms in 24 hours confirming the cancellation but I received nothing. So I called in again last week and the agent told me that an escalation was opened and she cannot close it from her side, so she emailed escalations again and I was told (again) that I would receive a sms in 24 hours confirming my cancellation. I am STILL waiting to hear back from Vodacom! They are forcing me to stay in a contract which I do not want. I am in my full right to cancel. It seems I'm going to have to take legal action to just change my account to prepaid, It is completely ridicuous.