Sorry to hear you are having problems accessing email. Do you use a client or is that Webmail related? We are aware of an issue with Webmail at the moment F005154348 estimated fix 13-MAR-2017 although that was raised yesterday not when you posted.
It may be worth considering setting one up as it can be a bit friendlier than Webmail and at the moment that should be working. We have a handy guide that may help Using Virgin Media Mail with Mail Clients