Hi @dancpalmer, thanks for your post here in the community although I'm sorry to hear of your concerns.
As @Graham_A has suggested, part of the T+C's at Virgin Media is that any email addresses that we provide (NTLworld.net, Virginmedia.co.uk or Virgin.net) are disconnected as soon as 90 days after you disconnect with us.
All these email addresses do require active cable services in order to carry on working, but in your case, it appears your email address has been caught much later on in the sweep to be closed off - your email address is what's known as an "orphaned account" due to having no active services it's tied to.
I do apologise for any inconvenience this respons will cause you, but I would recommend creating a new email address as soon as possible.
Many thanks
Tom_W