i recently had the same issue. We found ours only 6 inches from her cage about 16 hours after she was last seen in it. i would say recheck everywhere. With the help of a friend it took us 4 hours to find her. and where we found her my wife and I both looked several times. just think of small spaces that would be dark and about the same size as your ball. they like a tight hide so nothing is really to small.