Vodacom refuses to cancel my contract after 20 years!

I wanted to cancel my contract with Vodacom, which I have had for over 20 years and move on to a pay as you go scheme. I went into the Vodacom Store in Cresta Centre last month (January 2020) and was told that they couldn't do it for me, I had to phone in (***). I did so and was assisted by a very knowledgeable agent, who informed me that the contract would be cancelled from 1st February 2020 and that I would receive a sms to confirm this. Unfo urtunately none of this happened. On 1st February I was credited with my regular mix of data, calls, etc.. I spent over an hour holding on (45 minutes) and speaking to an agent who couldn't assist me and eventually said that they were off line and that she would call me back when they came on line. I have waited over 48 hours for this call. How long do I have to wait?