The online advertising company at the center of Verizon’s “zombie” cookie controversy cannot avoid a proposed class action lawsuit filed by Verizon Wireless customers, a federal appeals court ruled this week.

Turn, Inc. is an online advertising clearinghouse that allegedly attached un-deletable tracking cookies to Verizon customer identifiers to collect and send their Web browsing and usage data to Turn’s servers. Verizon customers Anthony Henson and William Cintron filed a proposed class action lawsuit against Turn on behalf of all Verizon customers in New York, but the company argued that the customers should be forced into arbitration.