HELP!!! Coarse Poofy Thick hair problems?

Okay i have EXTREMELY thick and coarse hair. And I dont know what to do with it! The only thing that tames it is flat ironing it. And i know that flat ironing it is bad for your hair and my hair was dry before i started straitening it. btw after i started flat ironing it, it becamse sort of wavy and even poofier. I want to find some way that doesnt use heat in which i can tame this mess. When i dont flat iron it, it looks ridiculous. It poofs out to my shoulders and its coarse and not nice to feel. I cant whip it into a ponytail either because it looks retarded because its so HUGE. I've tried de frizz stuff and different products. They dont seem to do anything. help what do i do? its a medium length it comes to the middle of my shoulder blades.