A report Tuesday indicated Facebook had been paying people $20 a month to get them to install an app that allowed Facebook to collect a ton of data off of their phones.

Facebook installed the app on people’s iPhones using an Apple program that was designed for big companies to distribute internal software.

On Tuesday night, Facebook said it had pulled the Facebook Research app.

But on Wednesday morning, Apple said Facebook’s enterprise certificates had been revoked – suggesting that its policies, rather than a choice by Facebook, were the reason the Facebook Research program had ended.

This isn’t going to help the frosty relationship between Facebook CEO Mark Zuckerberg and Apple CEO Tim Cook.

As of Tuesday, Facebook had long been paying people $20 a month to download an app called Facebook Research that essentially gave the company full access to collect data from their phones, including which websites they visited, the messages they sent, and all the apps they used, according to a report by TechCrunch’s Josh Constine.

The Facebook Research app wasn’t available from Apple’s App Store, though, because Apple’s platform bans apps that collect that kind of data. Instead, it’s “sideloaded,” or installed through a separate, more technical process that big companies use to install apps intended for internal use.

But it now seems as if the Facebook Research app violated Apple’s enterprise-certificate rules, specifically the rule that the sideloading process be used only by company employees. Facebook recruited people to use its research app through Instagram and Snapchat ads, and those who signed up were instructed to download the Facebook Research app by sideloading it.

Apple says it took the dramatic step of revoking multiple enterprise certificates from Facebook, potentially compromising not just programs like Facebook Research but also other iOS apps in development internally at Facebook.

Here’s Apple’s statement:

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“We designed our Enterprise Developer Program solely for the internal distribution of apps within an organization. Facebook has been using their membership to distribute a data-collecting app to consumers, which is a clear breach of their agreement with Apple. Any developer using their enterprise certificates to distribute apps to consumers will have their certificates revoked, which is what we did in this case to protect our users and their data.”

This doesn’t mean you won’t be able to download Facebook off the App Store, but it does mean Apple believes that certain internal Facebook apps violated its policies.

But Facebook initially said it broke up with Apple – not the other way around.

On Tuesday, Facebook initially said it stood by the Facebook Research app and didn’t have any plans to pull it. But it changed its tune Wednesday, eventually confirming to Business Insider that the program was shutting down on Apple devices. (Facebook did not immediately answer whether the same would be true for Android.)

Facebook appeared defiant, with a statement from a company representative saying that the Facebook Research app wasn’t secret and that the participants were paid to participate.

Here’s the statement from Facebook:

“Key facts about this market research program are being ignored. Despite early reports, there was nothing ‘secret’ about this; it was literally called the Facebook Research App. It wasn’t ‘spying’ as all of the people who signed up to participate went through a clear on-boarding process asking for their permission and were paid to participate. Finally, less than 5 percent of the people who chose to participate in this market research program were teens. All of them with signed parental consent forms.”

While it might be surprising that two of the world’s most valuable companies are arguing over who broke up with whom, the relationship between the two companies has gotten markedly chilly in recent years.

Apple executives have argued that Facebook turns its users into a product for advertisers, underscoring Apple’s pro-privacy stance, and Zuckerberg has called Cook’s criticism “glib.”

Reportedly, Zuckerberg even asked his employees to use Android phones and not Apple phones after Cook criticized Facebook in a televised interview. Facebook even confirmed the conflict in an official statement.

So while it’s unusual to see big companies publicly feuding like this, the fact that Apple has become one of the strongest checks on Facebook’s desire to collect more user data suggests that the relationship will remain strained.