There are two songs specfically, Skyline by Chris Webby and E.T by B.o.B ft. Lil wayne that will not play on spotify. The album Chris webby's song is on sometimes doesn't show up and won't play and other times it does. The B.o.B song is part of a brand new album called Ether and it says 12 songs and theres only 11 shown. this song is supposed to be the 12th. On the computer it shows the song but won't let me play it? Why is spotify doing this?
Spotify would love to have every song available everywhere but it all comes down to licensing. Spotify adds thousands of tracks everyday and fingers crossed they appear soon. In the meanwhile, you can ask the artist why their music isn't on Spotify yet. Let me know if there's anything else.