A federal appeals panel on Tuesday rejected a digital advertising firm’s effort to invoke Verizon Wireless’ arbitration agreement to push a subscriber class action over data collection practices out of court.

Verizon customers Anthony Henson and William Cintron in 2015 sued Turn Inc. in U.S. District Court for the Northern District of California over claims the internet advertising firm unlawfully collected browsing histories and other data with “zombie” cookies that consumers could not detect, block or delete. The plaintiffs, suing on behalf of all Verizon customers, accused Turn—which had a contract with Verizon to deliver ads to mobile subscribers—of recreating the cookies after users deleted them and proceeded to collect data without their knowledge.