If you get a refund of the purchase price and the original shipping, you're not being defrauded.

When you use eBay, you agree to abide by their rules. Their rules are really quite clear - if the seller sends you an item that is not as described, you're entitled to a refund of the purchase price and the original shipping, contingent upon you following eBay's rules and returning the item to the seller.

Go ahead and stand on principle over the cost of shipping the item back to the seller if you think it will make you feel better, but expect that if you do, eBay will find in favor of the seller and you'll just create more problems for yourself, including the immediate reversal of the refund from your PayPal account AND a freeze on both your eBay and PayPal accounts until you get it sorted out.

Stomping your foot won't change their policy, and won't get you anything more than what their policy says you're entitled to.