A few days ago Spotify claimed to be discriminated against, this was because the latest version of the Spotify app was rejected by the App Review process.
They claimed all kinds of things (ReCode):
Spotify says Apple is “causing grave harm to Spotify and its customers” by rejecting an update to Spotify’s iOS app.
“It continues a troubling pattern of behavior by Apple to exclude and diminish the competitiveness of Spotify on iOS and as a rival to Apple Music
Apple have since replied to Spotify with a lengthy letter, which you can read in full at BuzzFeed.
We have always believed that competition makes us all better. It drives the best products and services for our customers. We've invested i a tremendous amount so developers have the best ecosystem for creating and distributing apps. You know this because Spotify has profited greatly from your use of the App Store we developed.
Our investment in the App Store is not trivial - any great retailer will tell you there is an incredible amount of effort that goes into maintaining their store. However, if a customer chooses to sign up for a digital product outside of the App Store, the developer does not pay us anything, and their content will still work on Apple devices. To imply that Spotify should not have to pay to avail itself of the benefits of Apple's hard work, just as every other developer does, would give you a tremendous advantage over other developers. It's simply unfair and unreasonable.
I'm completely on Apple's side for this one.
It's the rules that every other developer has to follow, so why should Spotify be any different? Also if Spotify aren't using the built-in subscriptions/in-app purchases to manage the subscriptions, then what are they providing Apple? They get to use the App Store infrastructure, but they don't want to give anything back?
Well, I'm glad I'm an Apple Music subscriber.