I'm afraid that this forum rarely offers a fast response by Virgin Media, and I'll be surprised if the forum staff are able to pick up your message, get it investigated and fixed in time for your meeting. Hopefully the work is already underway and it'll be back on soon, but if not you may have to resort to other strategies.
I was in exactly the same position a couple of weeks back, and had to resort to setting my phone up as a wireless hotspot, connecting the work laptop to hotspot, and using mobile data for half a day. Fortunately updating and sending emails and a few conference calls don't use vast amounts of data, and the slow speed I get on mobile (10 Mbps) was still enough to keep me online and connected to the online meeting.
Thanks for using the forums, however I am sorry that the time scale didn't help this issue. We usually let the community, like Andruser who gave some really good advice, time to comment and offer help before we scoop posts up ourselves.
I hope the advice above worked with the hotspot, thinking outside the box definitely helps in these kinds of situations. However if you're still experiencing issues with your service please let us know and we can look into it further.