Please help! No account details

I have Virgin media broadband since August but have never been given an account number and never had an email from them. I have tried to call many times but noone can help me as I don't have security details. I have never been asked to create memorable word. The person on the phone asks me my last direct debit date but I got a special offer with free credit so they haven't taken any money yet. When I have checked my bank a direct debit has not been set up. It also says my email address is not valid. All I have is my landline number and personal details. It is like they don't know I exist!

I desperately need to access my account but nobody on the phone can help me. Please can you help??