No, I haven't tried it again. My stamp fell off the first time too. I think I did stamp with it eventually, if I remember right ... but I can't remember the exact situation. Seems like I pressed the stamp to it pretty firmly, but some definitely fell off. Maybe the stamp that worked was already a bit sticky from a previous mounting option?
Maybe once we get home from Denver I'll get a chance to try again. I'm sorry you didn't get a better response from POD, Daria. I think I did try washing the rubber in case it had some sort of manufacturing residue on it ... don't remember if it made I difference, but I don't think it did.