In my experience Amazon is much worse than eBay for buyers. With eBay at least you can get your money back.
Amazon bought out Zappos years ago, not specifically to take over their product line, but to get a hold of their customer service department. Amazon understood that Zappos had build a business culture that had a really good thing going, empowering their customer service reps to keep good customers happy, and they wanted to fold that into their own brand.
I've had several experiences like the OP's, and have never had Amazon drop the ball. The worst case scenario has been for them to ask me to put the item back in the box, slap on a new label, and send it back for a full refund. Half the time they just tell you to keep the item, and you get the full refund anyway.
If the item was sold as new, I certainly would not stand for receiving something used. On the other hand, I've purchased "like new" items from Amazon at deep discounts. The items in question guarantee that they will work, but may have cosmetic blemishes. Most times, it's just a damaged box. The few times the blemish has affected the function, they've had no problems with me returning it.
eBay is similar, though it takes much more time and effort on the buyer's part. And recently, I've had a Chinese seller weasel out of refunding me when they sent the wrong item. I'm quite pissed at eBay over this one...
