If the sunglasses you got can be categorized as worthless item then parhaps there is a way. Contact customer service via chat in message center. get past bot questions to talk to live agent, explained you got scammed with worthless item and ask for exception to send back.
Some members mentioned that they got refund from PP if you provide a tracking number showing you did ship, so you can actually ship an emoty envelope and get valid tracking number, might still cost you over $30 (max PP will reimburse you for return shipping cost, have to activate that feature in advance) but you'll be out less money and make the scammers pay. However, I'm not sure if that is standard PP practice for refunding after proving return shipment.
Best to get clarification on what PP's protocol is regarding return shipment and subsequent refund. Some had reported that the seller has to confirm receipt o return item before PP will refund, in that case, if you're convinced the seller is a scammer, don't bother sending it back, for obvious reasons.
