Are you a virgin media broadband customer? Email addresses require an active broadband service.
Is the virgin.net address linked to your billing account? When you sign in, it would show on the my profile page, or manage accounts tab. If not showing, it is probably an orphan address.
When the Forum Team reach this thread, they will be able to double check your account by private message, and possibly request a Move & Transfer if you meet the necessary conditions and the IT department can do the action. If you are not a customer, they can arrange for complete deletion of the mailbox from the VM servers so that you are not inconvenienced in the future with spam or hacking.