Steve - I am going through the same thing as you (I've just posted a message myself having received a bill for £90+ instead of the expected £46), this being the fourth time this year. The support is pretty shambolic - like you, I just need an email address that I can use, rather than going through a chatbot, or having to have a long phone conversation to explain the differences between my contract and my bill. Make sure you raise a formal complaint, and keep a copy of each complaint you raise. I may be about to go to the ombudsman and, looking back through the text of my complaints, I am sure that I have a 100% rock solid case to exit the contract.