It's pretty well reported that BT routers are causing problems, it is something to do with Parental Control settings, they are sorting a fix for it although not implemented yet.
The Virgin guy did to you what they do to all customers, fobbed you off, they are told to just bluff there way through until the third call or if the customer stays on the phone longer than 40 mins, even then you will be lucky.
Hope that helps...