I would give it some time. There was one time that I needed to contact someone on ebay about an item and didn't hear from them for quite awhile. I emailed a few times, but still hadn't heard back. I was a little irritated, but at the same time, I know unexpected things can happen in life so I just kept patient. It turned out that she had gotten into a car accident. She was still recovering, but was super nice and tried to contact me as soon as she was able to.
So hopefully nothing like that has happened to your buyer! If her feedback was fine, then you might just need to wait a little more. Good luck though