Twitter has rejected Elon Musk’s allegations in a Delaware court that he was tricked into signing a deal to buy the social media company, calling it “improperly credible and untrue.”

Musk made the allegations in a counterclaim he filed last Friday, which was not announced until Thursday.

“Wall Street bankers and lawyers tricked into signing $44 billion merger deal according to multi-corporate billionaire co-founder Musk. This story is unbelievable and false,” Twitter said.

It’s the latest chapter in what could be a major legal battle between the world’s richest man and social media giants.

The San Francisco-based company has been scrambling to deny its fate for months, while Musk has tried to back out of the deal after he said Twitter was withholding information about fake accounts.