Billionaire Elon Musk on Friday moved to back out of his $44 billion deal to buy Twitter, citing continued disagreements over the number of spam accounts on the platform.

While Musk may want to end his bid for Twitter, it’s not as easy as just walking away, according to legal experts. Instead, Musk likely faces a long battle ahead with Twitter in court that could take many months to resolve.

Twitter’s board is in a very difficult position, said Ann Lipton, a professor of corporate governance at Tulane Law School. “They can’t just say, ’Alright, let’s spare us the pain, Elon we’ll let you knock the price down by $20 per share, or we’ll settle, we’ll agree to walk away if you just pay the billion dollar break fee. I mean, Twitter is just not in a position to be able to do that.”

Doing so would risk triggering a lawsuit by Twitter shareholders, she added. Twitter shareholders have already filed a lawsuit against the company and Elon Musk himself over the chaotic deal.

Merger agreements are “very hard to get out of,” and so far, Musk appears to have provided insufficient evidence backing up his claims that Twitter lied about its spam figures, Lipton said.