I'm sorry that you're having issues accessing your online account. For my understanding, please can you clarify if your email address has been associated with a different Virgin Media account number and also, if you've previously successfully accessed your online account since you had your existing account? I ask this, because it sounds as though your email address could possibly still be associated with a former account.
Thank you for getting back to me. It's a bit complicated - I am getting emails on the new account but this address was used as the user name of the old (now closed, different address, account) but I think you are right.
When I tried to register again, I used a different email address as the user name but it did not let me complete registration.
Its difficult because I don't really want to go through the effort of setting up a whole new email just for VM emails!