Billionaire Tesla CEO Elon Musk said on Friday he had canceled his $44 billion deal to buy Twitter, adding that the social media company had failed to provide information about fake accounts on its platform

Twitter shares fell 6 percent in post-closing trading.

Musk’s lawyers said in a notification to regulators that Twitter failed or refused to respond to multiple requests for information about fake or unwanted accounts on the platform, which is essential to the company’s business.

Musk has threatened to block the deal unless the company provides evidence that the fake accounts are less than five percent of users who see ads on the social media service.

Twitter did not immediately respond to a Reuters request for comment

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