“Having decided that it would rather enjoy the benefits of the App Store without paying for them, Epic has breached its contracts with Apple, using its own customers and Apple’s users as leverage,” Apple said in a court filing Friday.

Epic is set to ask a federal court on Monday to force Apple to restore the Fortnite app to the App Store, and block the company from cutting off Epic’s developer tools and limiting its ability to provide key graphics technology to other apps. Apple is urging a judge in Oakland, Calif., to reject Epic’s request.

The dispute is shaping up into a major antitrust showdown as friction between developers and Apple has been building for more than a year. Developers have been increasingly calling out Apple’s App Store fee policies and rules, complaining they are unfair and only benefit the company’s own services.

Apple has said Epic made trouble for itself by offering customers a way to directly buy items for Fortnite and circumvent the App Store fees. Apple said it won’t bend its rules for Epic.

Epic Chief Executive Officer Tim Sweeney emailed Apple on June 30 seeking to set up its own competing Epic Games Store app through the App Store but was rebuffed, according to Apple’s filing. Despite being told that “Apple has never allowed this,” Epic went ahead and launched its own storefront on Aug. 13, Apple said in its filing.

This is “egregious behavior” prohibited under Apple agreements that “can lead to removal from the Apple Developer Program,” Apple said in its filing.

“Apple has offered Epic the opportunity to cure, to go back to the status quo before Epic installed its ‘hotfix’ that turned into its hot mess, and to be welcomed back into the App Store,” Apple said in its filing. “All of this can happen without any intervention of the Court or expenditure of judicial resources.”

Epic didn’t immediately respond to a request for comment.

Spotify also has been sparring with Apple, and this week news publishers confronted Chief Executive Officer Tim Cook over why they can’t qualify for a discounted fee — 15% — that Amazon.com Inc. gets for its Prime video app.

Match Group Inc., operator of many popular online dating apps, said it’s backing Epic but has stopped short of joining the court fight. “Apple uses its dominant position and unfair policies to hurt consumers, app developers and entrepreneurs,” Match.com said in a statement.

Of the 2.2 million apps available on the App Store, the 30% fee is billed to more than 350,000. Apple reduces the fee to 15% for subscriptions after a user signs up for more than a year.