Facebook is suing the law firms that represented a man claiming he owned half of the social media company in a 2010 lawsuit. So reports the San Francisco Gate.

A DLA Piper associate’s e-mail stating “that bill shall know no limits,” which surfaced in the course of discovery after the firm sued a client for failing to pay a large bill, has drawn attention to flaws in the billable hour system that law firms use to determine the fees owed by most of their clients.