Spotify announced on Wednesday that the company has filed a complaint against Apple with the European Commission, a regulatory body responsible for keeping competition fair and nondiscriminatory.

Daniel Ek, founder and CEO of Spotify, penned an article claiming that Apple has created an unfair “ecosystem” by “deliberately [disadvantaging] other app developers.”

Apple operates a platform that, for over a billion people around the world, is the gateway to the internet. Apple is both the owner of the iOS platform and the App Store—and a competitor to services like Spotify. In theory, this is fine. But in Apple’s case, they continue to give themselves an unfair advantage at every turn.

To illustrate his claim, Ek states that Apples requires Spotify and other digital services pay a 30 percent tax on purchases made throgh Apple’s payment system, including upgrading Spotify’s Free to Premium service. “If we pay this tax, it would force us to artificially inflate the price of our Premium membership well above the price of Apple music. And to keep our price competitive for our customers, that isn’t something we can do.”

Ek says that if they choose not to use Apple’s payment system, and forgo the charge, then Apple applies a number of “technical and experience-limiting restrictions on Spotify.”

Spofity is asking that apps be able to compete fairly on the merits, that consumers have a real choice of payments systems, and that app stores should not be allowed to control the communication between services and users.

Among others, Apple does not subject apps like Uber or Deliveroo to the Apple tax.