According to a new Bloomberg report, Apple Inc. faces a class action lawsuit from UK app developers who allege its commission charges of as much as 30% on App Store sales created an anti-competitive tax on the nation’s tech industry.

The iPhone maker could be on the hook for repaying as much as £785 million ($995 million) in fees to as many as 13,000 developers, according to UK competition policy professor Sean Ennis, who’s leading the claim. Judges at the UK’s Competition Appeal Tribunal paved the way for the suit to continue after dismissing the US firm’s arguments to block the case.

Apple has been in the crosshairs of regulators across the world over its app-fee policies, and announced changes in January aimed at appeasing European Union watchdogs. Those changes have come under EU scrutiny, amid concerns the new terms actually made the situation worse for developers.

Apple charged commission fees on UK-based app developers who sold their apps via the App Store or made sales to iOS device users via subscriptions within their apps from July 25, 2017 onwards, Ennis said in court filings.