Spotify is enraged at the way that that Apple's App Store approval process is being exploited to put down other competitors that are directly a threat to Apple's own music streaming service: Apple Music. Apple recently denied a request from Spotify to update its iOS app, which is what's currently causing conflict. Here the problem lies in the way Apple requires subscription based services to use iTunes billing in order to sell service to app Store users. What's unfair is while Apple doesn't require that Apps use the iTunes billing system at all, it doesn't allow apps to use any other...
Source: http://www.gsmarena.com/spotify_calls_apple_anticompetitive_upon_denial_of_spotifys_new_ios_update-news-19147.php
