Hi - I took a look at a few of your listings and in one particular example (a book), the listing says "ships worldwide", yet when I entered "United States" in the box under the shipping section to get rates, a message appeared saying the information was not available.
My guess is that although you've indicated that you ship worldwide, you haven't actually put any rates in for the United States. Entering an exception in your preferences isn't likely going to change that if there are no U.S. shipping rates specified, although if worse comes to worst you can probably invoice your buyer directly through Paypal.
It looks as if you're using the shipping calculator in some of your listings. I use flat rate shipping only, so I'm not familiar with how the rates are set up on the calculator, but I would think you'd have to revise your item in order to include U.S. shipping rates. Perhaps someone who uses calculated shipping will know.
