Joan Rivers' estranged ex-manager is shticking it to comedy's bigmouthed matriarch with a federal lawsuit claiming unpaid fees and public ridicule.

Billy Sammeth says Rivers stiffed him out of commissions and expenses worth $179,000 and lampooned him in a documentary, "Joan Rivers: A Piece of Work," as "unreliable" and missing in action.

"It's not true he was missing. The fact is that Joan needed to save money, so she cut Billy," Sammeth's lawyer Susan Chana Lask said. "She makes a big scene out of losing her 'best friend.' If he's her best friend, why lie and cut him off at the knees? That's the worst part."