I red this so many times about missing gems and that people accidentally spent them and guess what happend to me - on my iPad store game froze and I tapped couple times and soon enough I exchanged my 10 gems to 10.000 coins, whatever...
But more funny then day later on my iPhone ID 77772222ok I had 17 gems and I log in one day only 7 left ))
Can't they finally fix it or they do it on purpose to force you buy gems?
Laim