I would email them if you hare now home and give them your photopass # and then let them know what day you were there and approximately what time and the what your kids were wearing. (if you have a picture that you can send them), then they might be able to locate them. Also check on the photopass site because I believe they have instructions on how to located missing photos.
I saw them once helping someone in the park search for their pictures that were misplaced.