Your actions seem fair, and with refunded money, he's not harmed. It may be his usual attitude, but perhaps there was a chip in the group that he REALLY wanted, or considered a "sleeper" with unrecognized value.

If you want to make him happy, I'd point to your 100% feedback with large number of transactions as an indicator that you're not an intentional deal-breaker. Then offer to sell them to him, at his choice, once you have them returned to you. You could do it as a "second chance offer" via ebay. Personally, I would offer them to him at his final bid, but give free shipping. Sounds imminently fair deal to me, if I were offered such an option.