Mission Control

I can't get my mission control app to open. Any of the shortcut keys don't work, my tracking pad doesn't let me use the 3 finger swipe, and even when I try to open it through my apps it does nothing when I click on it.

I have tried everything I can find on the topic, even called apple on the phone. we ended up re-installing the OS, but I just got back on and it still isn't working. Any ideas what I could try?