Welcome to eBay selling, where sellers are treated like they've just been scraped off the bottom of your shoe and buyers can do no wrong. This buyer knew what they were doing. They knew if their demands weren't met, they could then lie and eBay would believe them. I don't have anything else to add to what DG wrote. She summed it up perfectly. Don't forget to change your return policy to no returns and add that buyer to your blocked buyer list.

Please keep us posted. There are plenty of sellers here who are fed up to the back teeth with scamming buyers (and eBay encourages them).