Quick note - the error message reported by the OP is only displayed when access is via VM's web page. OP also says last access was several days ago. Perhaps last weekend?
The error message appears in two circumstances. When VM security have locked the account because of spam being sent using the account credentials. Or it is in the process of being deleted as an orphan. As the OP says the address is not associated with a current VM broadband account the second options seems the more likely, in our general experience of these issues.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks
About a week ago. I use both your web page & my mobile to access emails& both have stopped working. I think my account may have been hijacked to send spam so has been closed as a precaution however changing my password doesn't seem to have helped.