This is not really that surprising. Most items that are returned are never resold as "new" anyway. Return goods are thrown in the trash right away or sold with a discount in their own stores or sold to discounters.

They just offered return shipping as a service to the customer. It was all smoke and mirrors in the first place. If return shipping cost more than selling to discounters or handling the trash they will just let you keep the goods.

The damage Amazon, Zara, Primark and the likes are doing to this world is gigantic. Destroying the environment, tearing down worker rights, using close to slave labour, shipping their trash to poor countries, wasting fuel and resources.