This morning, I collected my free coins (approximately 8,000) then closed the app without playing. Four hours later, I went to collect again. I didn't look at my total before hitting collect but when I went to play the game, I still had about 8,000. Is there a limit on how much coins you can have/collect so that you can't save them up? Or am I totally mistaken about how many coins are collected every four hours? I'm on level 18 about to hit 19.