Professional Bull Riders, the rodeo subsidiary of Endeavor Holdings, has filed a federal lawsuit against its website designer, accusing the firm of shoddy and incompetent work.

PBR contends that iX.co delivered a site that struggled to play video highlights of bull-riding events — a core feature for fans of the league. The suit also contends that when PBR complained and sought a refund, the web developers took the site hostage, preventing PBR employees from accessing it, in order to gain leverage in the contract dispute.

“As a result of iX’s retaliatory action — which amounts to a show of force in response to a refund request from a highly dissatisfied customer — PBR’s website is degrading, and it cannot fix or reconfigure its communications with its customers in any significant way,” the suit alleges. “iX’s conduct has done significant harm to PBR’s business, its reputation as a premier provider of athletic competitions and news, and the goodwill of its fan base.”

iX.co is part of Wanda Sports, which is principally owned by China’s Dalian Wanda Group. Endeavor, which owns PBR, also owns WME and a majority stake in the Ultimate Fighting Championship.

Both companies filed to go public this year. Wanda Sports, which owns the Ironman triathlon competition, had a rocky debut on the NASDAQ exchange in July. Endeavor dropped its IPO on Sept. 26, a day before it was to go public on the New York Stock Exchange.

iX.co claims a number of sports teams and leagues as clients, including NASCAR, the PGA, and the Chelsea football club. It also lists CAA — WME’s principal rival — as a client.

According to the lawsuit, iX promised to use “open source” code in designing the site, but instead used proprietary software, called Corebine, giving iX “an effective monopoly on the knowhow required to service the code.”

In addition to the video playback issues, PBR also found it impossible to adjust its advertising configurations on the site, according to the suit. After the relationship with iX broke down, PBR hired new web contractors, who have tried to work around the proprietary software.

“Time and again, when new providers have attempted to remedy the problems with the website — especially its critical video playback functions — they have been stymied by the emplacement of Corebine modules and elements that are completely unfamiliar, are nonstandard to the industry, and cannot be manipulated without massive additional learning and expense,” the suit contends.

PBR is seeking $300,000, plus a full refund.