Cannot get character piece

I have three character pieces that I have half of and I am up to 35 million coins. The fertilizer fun pack only gives me minions and I still have half of a disco chomper that I can't get. I also only get minions from wondrous pack and I have a scientist and half a superhero. I got half of the disco chomper six months ago. I want to know why on earth should waste my coins on 35k packs of minions, then I got brilliant idea and thought hey maybe when chompers rotate in and they sell the packs I could get it that way and all I got were more minions. EA when are you going to stop ripping us off if people have spent that much time and effort fix your drop rate or have a dollar amount you have to reach to achieve these goals.