Non-existent support when trying to cancel a service

I’ve been trying to cancel my Netstar service since my car is no longer in a driveable condition. But it’s impossible nowadays to get through to a human for non-emergency services at Netstar, I am just redirected to the app or a chatbot. My emails were answered very hurriedly by agents and subsequently marked as resolved every time even though that is not the case. Still haven’t been contacted by anyone regarding the cancellation. Now it’s the 1st of June and another debit order goes off for a service I don’t want, because their people couldn’t get back to me in time.