The EXACT same thing happened to me, I missed ONE rubber band and card when I was looking for them. I was using the strategy guide book. Anyway, I realized that I didn't see one point on the map, so I went there, and there it was! It was behind the locked door in the last area (the on in the huge building where you climb a ramp).
Anyway, if you want a suggestion as to how to find it, go to
this site and read over the location of each rubber band, if one does not seem familiar to you, and you don't think you where there check it out, I did the same thing (with the book).