I'm going to get him fired, but it seems I might be a hypocrite.
Why do you want to get him fired?
He got me fired first.
It is understandable to feel like getting revenge on those who get you fired. The hypocrite part is rudely bothersome, you don't need to do unto others this way as they did to you. Let God handle it for you, he has the wrath to see if it's fitting in this case.
Why should I just let him without paying him back for what he has done to me.
I understand the need for revenge, but it blackens your heart and won't make you feel better. You are better off just moving on.