From the movie “Betting on Zero” at Double Exposure: Investigative Film Festival and Symposium. (Zipper Bros Films/Double Exposure: Investigative Film Festival and Symposium)

The director of a documentary critical of Herbalife says a lobbying firm employed by the nutritional supplement company, Heather Podesta + Partners, tried to keep a Washington audience away from a screening.

Ted Braun, the writer and director of “Betting On Zero,” says 10 people who work for Podesta’s firm purchased 173 tickets — roughly half the seats — to a showing of the movie at the Double Exposure film festival Friday night at the National Portrait Gallery. The tickets, which the Podesta staffers bought in batches, were never picked up, and the seats went vacant, festival organizers said.

In a statement, Braun called the move a “deliberate attempt to thwart an interested D.C. audience from seeing our documentary.”

The movie is unflattering to Herbalife and its use of a citizen sales force. Its hero is hedge-funder and prominent critic Bill Ackman, who charges that the company’s tactics amount to a pyramid scheme. Herbalife has pushed back against the film, including buying the domain bettingonzero.com and creating a website critical of it. The company has also reportedly spent tens of millions, including on “Democratic operatives, three public relations firms and two law firms stacked with former prosecutors,” according to the New York Times, in an effort to counter Ackman’s campaign against the company.

Neither Podesta nor an Herbalife spokeswoman immediately responded to requests for comment.

In the statement, Braun noted that the screening was part of an event meant to highlight revealing films. “In the context of a festival devoted to investigative filmmaking such actions are particularly questionable and disappointing for a publicly traded company operating in an open democracy.”