Spotify says Apple is making it harder to sell audiobooks, an offering Spotify just introduced last month. The company called Apple practices “anticompetitive” and said it was “choking competition” in a blog post published just before the company revealed its earnings report on Tuesday.

Spotify says Apple’s rules make the process of buying an audiobook on Spotify “far too complicated and confusing,” adding that Apple changes its “rules arbitrarily, making them impossible to interpret.” Apple charges up to a 30 percent commission on purchases made in apps listed on the App Store, and bars certain developers from using or directing users to an external payment processor.

As outlined in a webpage Spotify specifically made to support its cause, the company says Apple rejected its proposed audiobook purchasing process three times because it went against the App Store’s policies. To comply with Apple’s rules, Spotify hides the price of its audiobooks and doesn’t let users buy content in the app. Instead, you select the book you want to buy and Spotify then emails you a link to check out on the web.

This makes it harder to compare prices, which you only find out about through the email. Spotify says this process “harms not only consumers, but, this time, also authors and publishers who now find themselves under Apple’s thumb.” As my colleague Ariel Shapiro pointed out in an edition of Hot Pod Insider, the process of purchasing an audiobook “is not the most elegant.”

This isn’t the first time Spotify has called out Apple. In 2019, the music streaming company filed an antitrust complaint against Apple in Europe, claiming the company is harming consumer choice by imposing its 30 percent “Apple tax.”

“In the absence of government intervention — in Europe, the U.S., or any other market around the world — Apple has shown time and again that it will not self-regulate and has no real incentive to change,” Spotify CEO Daniel Ek said in a statement today. “With our Audiobooks launch, Apple has once again proven just how brazen it is willing to be with its App Store rules, constantly shifting the goalposts to disadvantage their competitors.”

While Spotify could make purchasing audiobooks easier by using Apple’s in-app purchase system, this would subject each purchase to the up to 30 percent commission Apple charges. It would also make it more difficult for Spotify to compete with Apple Books. Apple didn’t immediately respond to The Verge’s request for comment.