Donating money to Vodacom every month

Vodacom decides to upgrade a number on my contract which I have not used for over 4 years on their own discretion and I just have to pay. No consultation no phone call and no you cannot cancel until 2028 ***. How does that work. Who in their right mind would upgrade a number you do not have do not use no phone for over 4 years just to donate more money to Vodacom. Please do answer that question who does that? Cancel the number that is all I am asking and I am informing you now I am going to stop paying you and you are more than welcome to black list me as I am fed-up with your poor service