Many sites send an email that you have to respond to to proceed. I noticed now for 2 days these take forever to arrive. Yesterday I sent an email to myself and that took 30 minutes when it did not even have to leave Virgin. Is there a problem? I see nothing on the service status page.
Further to this- my findings following my own investigations:
I had many emails I was expecting including tests from my own and others email accounts. To eliminate my PC being the problem I logged into webmail. No mails were arriving in my inbox. Then suddenly I got a load appear all at once. The emails are being accepted by Virgin (as no error reports are being returned to the sender)., but they are not appearing in my inbox.(At least not instantly or within a few minutes) . Then later - perhaps 30 minutes later - they all appear at the same time. I have no idea how email servers work, but it appears there is a bottleneck between the mail arriving and it appearing in my inbox. I have ticked the box 'email me when someone replies' but I presume I will not get that email for some time so I will check back here occasionally.
You would be far better off replacing Virgin's buggy and unreliable email system with a new email address with one of the large providers like Gmail, Outlook or yahoo. Or better still get your own domain. You can set up an auto forward from your VM address until your contacts all have the new address.
This will free you from all the problems that fill this forum, and preserves your email if you ever change to another ISP.