Activate Refunded Returns. You’ll be eligible for a refund on return shipping costs from your next PayPal purchase.
If you return an eligible purchase, log in to your PayPal account to find the original transaction.
Submit a request with proof of return** within 30 days of return and 150 days of purchase. Receive your refund, usually within 5 business days.
I’ve personally had nothing but success using this. Keep in mind though that if you have eBay Plus using that may be easier for items purchased on eBay. This works anywhere you use PayPal though.
They are quite stringent on the proof you can provide so I’d recommend doing a dummy form/application (not submitting it) so you know the information required before sending your item.