I can assure you they don't always give their modem/routers away for free. I was made to pay £60 for mine after i mentioned that my previous modem with separate router sometimes lost connection. In my case the guy said if i upgraded to they're 30mb package from my 10mb package I would be entitled to get it free of charge.
With that said, I phoned virginmedia support on monday and the modem/router hub they sent (the one i paid for) the power levels on it are too high. I asked would this be the cause of the connection dropping which he replied yes. He did go onto say that the connection is still fine, there's no issues with that just that the hub they sent the power levels are too high and will be sending out a replacement.