Dishonest, Cynical ****a shop tricks

Zero rating is appropriate because their customer service is non-existent. I cancelled my contract in the 24th month of my contract via their online portal which I was told is the only way you can cancel. They did not action it and quietly kept on charging me failing to deliver my statement to my email for the first time in 24 months. Now I discover my sim which I thought is lost inside the house has started using up data and my so called spend limit by itself. I try to call their call center to block the sim and the agent only said hello and then the call went silent. I tried calling again and the robot tells me to use the whatsapp self service portal and the details to do this have been sent by SMS to the very same number that I am trying to block. I call again without providing the number my call is related to and the call goes unanswered by a human for over 15 minutes uand counting... I then try to use their website and surprise surprise clicking on manage my subscriptions returns a 404 page not found error