It sounds to me like your seller might have had another buyer on the line all along. I have had a couple of deals that were in negotiations get sold to another person, and I live here in the US. It could be one of a couple things. It could be that the seller was just going to take the first person who actually paid. But more than likely, it was the overseas shipping. I have noticed over the years that a lot of sellers do not want to ship anywhere outside of the US - even if both parties realize it may cost more money and you can figure out whose paying for the difference. I have sold a couple bats to customers in Canada and have had no issue. As long as the buyer is willing to throw up a few more bucks for the shipping, I don't think its a big deal. But people will sometimes tell you that it creates more of a headache than its worth. I can't speak to every experience, just the couple I have had.
It's all about how much the seller really wants to move the bat, and how much that seller is willing to make a sale. I would imagine that a lot of guys would rather drag their feet to your offer in hopes that someone from the US makes a deal. Shady, yes. But that's the world we live in.
If I can make a suggestion for the future, tell people right away that you have a US address to ship to. If you keep up the 100% feedback, people "shouldn't" have a problem shipping to this US address. It might make things easier for you to make purchases.