I've used NordVPN for a few years. I'm just an occasional light user. Not had any problems with it. Got a great 4 year deal on their U.S. website back in July.
I used it to watch stuff on the Virgin Media app whilst abroad. I think VM now have ways to detect VPN or location to stop you using it abroad.
It's fairly trivial to determine if a particular IP address is an endpoint for a VPN, I'm sure Virgin have signed up with some service to do exactly that. The only way around is for the VPN provider to constantly provide new end points, at a rate faster than the services can keep up. Which is every bit as expensive as it sounds.