Loyal customer cannot stop contract

I cannot fault Vodacom's service and the personnel are in general very helpful and friendly. My problem is a cellphone contract for *** that I have cancelled on 18 September 2020 and still are being billed for. I have phoned on many occasions, gave them a good rating because they are friendly, but the number is just ''migrated'' and the next month I am billed again. I have emails (on the day I have cancelled it, I confirmed it with an email), have lodged complains from Vodacom outlets in George and Stellenbosch and phoned more than once. Today I went to the friendly branch at Stellenbosch Square again and they phoned for me. They gave me a reference *** (like the many I had in the past). I am a neurosurgeon and have been with Vodacom since they started in this country, which may be nearly 30 years, and was always treated well. Is this a misunderstanding? I have this week heard from a colleague who had a similar problem. I do not know what to do. What I am worried about is that these young people may earning a living by preventing contracts from being cancelled. If true, is the *******ion this country is fighting at the moment. I think the good name of Vodacom is worth much more than the few rand they are making. I have taken out two more contracts during this year, but this unsolved problem make me worry about future associations with Vodacom. Thank you for allowing me to state my problem