An Upper West Side synagogue allegedly threatened to...de-kosherize...a kosher restaurant owner after a deal went sour, according to reports.

Lincoln Square Synagogue on Amsterdam Avenue is reportedly involved in a legal dispute with Joseph Allaham, the owner of a number of popular kosher restaurants in Manhattan including Prime Grill and Bentley. The synagogue says Allaham stiffed them on $1.5 million after he agreed to partially finance a banquet hall in their new $50 million space; Allaham says the synagogue screwed him because construction was delayed, costing him revenue.

The synagogue wants to bring the suit, which is for $1.8 million, before the Beth Din of America, a religious court. Allaham is against this, since the synagogue's rabbi is a member of the rabbinical council that oversees that court.

Now, Lincoln Square's going all in—according to papers filed in court this week, they're threatening to pull Allaham's kosher certification. Allaham's restaurants have fed everyone from Madonna to Alec Baldwin, and though they might not require strict kashrut, revoking his certification would kill his business. "“For too long, the reputation of kosher food has not been good—people think of chicken soup, pastrami sandwich, and gefilte fish,” Allaham told Tablet Mag in 2012. “I came to the market and wanted to provide top-quality meat that is kosher.”