Okay, so I completed all the countries in the map, every upgrade is maxed, but some stamps are still missing, and I can't do anything more. The tips have pointed at Marshal Islands from the beginning, but nothing happens when I click there. It actually says "you are in Kiribati" - the only case where it doesn't display the correct country.
Hi vulpion! Sorry for this, it have a bug there, we had updated now! Tomorrow we will improve some other things. About some stamps that are still missing, some countries have a lot of stamps, and you need to paly again to find these stamps, some of stamps are random, and we're improve the game so you can get much more, even legendary stamps in the next update, tomorrow! By now, only the African countries have legendary post stamps, and you can replay after you find the person if you have missed some post stamp, all your current stamps is saved for the next replay, ok? Hope you enjoy!