Offline mode is disabled. I am connected to the internet at home, however spotify on my IOS device doesn't allow me to play music. Music in my playlist plays if i press 'shuffle' however i am unable to select songs myself to play, basically greyed with no option to press any songs. Anyways i tried the 7 day free trial of premium and this had fixed it temporarily, after the 7 days it went back to being unable to play anything even when connected to the internet.
FYI it works on my computer and can play music fine, it is just the Iphone that doesn't let me play music.
As @Ohtroye mentioned, with Spotify Free on mobile, you can shuffle your playlists and skip up to six times per hour. With Spotify Free on your desktop/tablet, you can choose the music you'd like to listen to. You can also upgrade to Spotify Premium to listen to all the music, wherever and whenever you want. Learn more here. Let me know if you have any questions.