Here's how the eBay Money Back Guarantee works.
The buyer complains.
The seller is told to send Return Shipping*.
The buyer returns the unwanted item.
The seller refunds.
The seller modifies his listing if necessary and relists.
NO RETURNS DOES NOT MEAN NO REFUNDS.
USED DOES NOT MEAN NOT WORKING.
*We can send return shipping labels to Canada easily, and to the USA through Shippo. For other locations, eBay can step in and arrange return shipping, which is then charged to the seller.