Virgin are not being entirely honest with you! I was upgraded at the end of October and haven't had any broadband since.
I spent a week on the phone to them before they admitted that the problem was with their upgrade. They told me that one in ten of their customers has the same problem and that there was a huge backlog.
Since then I have been ringing them every day. They tell me that I am still in the queue and will have to wait for their engineers to sort it out. They also promise to ring me with updates, but never do!
I would get back on to their helpdesk and say that you know they have a problem and you want it logging properly with the engineers. Just ringing the helpdesk does not mean they will report your fault.
I've had enough of it now - they seem incapable of doing anything, so I'm going to join O2 instead!