I am sorry to hear you had such a bad experience. This game, was it a OSX/iOS exclusive or cross-platform AAA game?
AAA, Call of Duty 4
Ah alright. Yeah that's the impression I get as well. Cross platform games would probably be better bought from Steam than MAS.
While games that might focus on Apple would be better through the App Stores.
[0]: http://www.macrumors.com/2015/11/17/apple-responds-mac-app-s...