Robeez shoes MIA

Several months ago one of my slippers went missing.  I eventually found it stuffed between my 4 yo son's trundle bed and his mattress.  I had also lost a single Robeez shoe of DD's.  I am saddened to report that I STILL haven't found it.  AND just last week, we lost another single Robeez shoe.  The first was lost somewhere between the changing table and the car.  The second was lost somewhere between the baby's room and my bedroom (not very far at all!).  DS denies involvement and a cursory search of his usual hiding spots has turned up nothing.  Good thing I keep buying Robeez for $2-3 a pair at garage sales!  Uuugggh kids!  The chaos!