That's not true. The second you accept compensation for the item posted the delivery company takes ownership of the goods and they are free to do with them whatever they see fit, including selling them if they are ever found.
The terms linked in my sibling comment expressly say otherwise. The title remains with the seller until they either deliver it or decide to dispose of it. Which is hilarious.
Transfer of Title. Title to a GSP Item remains with your Seller until such time as the GSP Item is successfully delivered to you or your consignee, at which time title to the GSP Item shall transfer to you or your consignee. At no time do eBay (or its affiliates), Pitney Bowes (or its affiliates), or the third party logistics providers, shipping carriers, customs brokers, freight forwarders, or other subcontractors under contract with Pitney Bowes take title to a GSP Item.