That sounds familiar.

It’s the first thought that crossed both Dan and Ben Volach’s minds after Apple announced Sign in with Apple at its annual developer conference this past June. Specifically, the part of the new feature that allows users to generate a random email address for apps when signing in, so they never need to hand over personal information to a third party.

A few days later, still reeling from the shock of seeing the technology they patented announced on the world stage, the Volach brothers’ email app, BlueMail, was removed from the Mac App Store. Coincidence? They don’t think so.

The pair are suing Apple for patent infringement, but they’ve also just published an open letter to Tim Cook, asking the Apple CEO to restore BlueMail to the Mac App Store—despite the ongoing litigation—so they don’t lose their business.

“It has now been over five months since Apple removed BlueMail from the Mac App Store,” Ben Volach writes in the open letter. “In these five months, our company’s future has been put in jeopardy. Our users do not understand why BlueMail stopped being available on the store, nor can we give them a date when it will be restored.”

Photograph: BlueMail

Dan and Ben Volach told WIRED their company doesn't have the resources to pursue the lawsuit if their MacOS app isn't back on the App Store, considering the litigation can take time. It doesn't help that Apple's legal team has allegedly asked for an extension to prepare its defense.

"Without a presence on the Mac App Store, we cannot continue forever," Ben Volach writes in the letter. "No small developer has your resources and these extensions are more than preparation; these delays leverage your resources and control over our ability to generate revenue. And so, when you delisted our app, we lost our voice."

Anonymized Emails

Dan and Ben Volach are the creators of BlueMail, an email app founded in 2013 that prides itself on supporting multiple services, from iCloud and Gmail to Outlook and Exchange. The app—which has 10 million users globally, according to Sensor Tower—is also cross-platform, supporting Windows, iOS, Android, Linux, and, until a few months ago, MacOS.

Last year, the app was found to be sending users' passwords to the developers, but the company issued an update that reportedly rectified the issue and claims it doesn't store emails or passwords on its servers.