I can normally stream Spotify on longhauls, though I have to make a point of starting and thus updating Spotify on the ground just in case it starts trying to download 60 new tracks when in the air. My experiences with BA's Wifi is that I can usually get it to work quite well, apart from inner Greenland and the seriously cold bits of Canada, but once in a while the system won't work for any passenger. I have also had refunds without quibble.