Update: I got on the phone with eBay. My harp was just a small part of a very large scam involving many high-end musical instruments as well as other items. It seems a postage stamp dealer in the U.K. was hacked, and someone in California was using the account to try to rip people off. Fortunately, eBay responded quickly, all the fake listings are gone, and the seller is back to being a legit stamp dealer. I just feel bad for the stamp dealer, and for the many people who had bid on fraudulent items. What I learned: always check to make sure the item and the seller are in the same place!