When you order a product off of the Internet, it is very often that the product is not actually shipped by the seller itself. Many individuals and companies hire shipping companies to fulfill and ship product that they might sell.
According to the Complaint in this case filed by Lee Law PLLC, OtterBox, the cellphone case company, discovered a ring of counterfeit sellers who are using a shipping company’s services to distribute counterfeit cell phone cases to unsuspecting purchasers on eBay. The Complaint alleges that 4PX Express USA Inc. was put on notice several times of the illegal sales but they continued despite OtterBox’s requests to have it stop. You can read the Complaint here.
Under trademark law, not just the seller of counterfeit products can be held liable for the infringement but also anyone that distributes the product.