Because the game is a mess ... that's why.

So many things need fixing, for a game that makes a LOT of money from in-app purchasing, they should be made keep their game to a certain standard.

I complained about an app game in the past to itunes. I had spent a lot of money on it and the game got worse, with more bugs after every update - I got every cent back. That game is still one of the most popular games in the app store so it didn't hurt them, but I wasn't happy that they never listened to players suggestions, never fixed bugs or annoying issues, but of course continued to take their money ...

I'm tempted to go do same on this game, because they are the most unresponsive, uncaring devs I've come across yet. And I have spent a fair bit on the game the past 4 months.