Four former top Twitter executives who fired by billionaire Elon Musk when he bought the social media company are suing him for more than $128 million in severance pay, according to a lawsuit filed Monday in a California court. Former chief executive officer Parag Agrawal, former chief financial officer Ned Segal, former chief legal officer Vijaya Gadde and former general counsel Sean Edgett claim that Musk fired them “without reason, then made up fake cause and appointed employees of hisvarious companies to uphold his decision,” according to the filing. There was initially no response from Mu…