I want to make a fursuit, how do I?
I'm sure there is some sort of action you can take but I think you waited a long time you should have complained about your boss's erratic behavior and irresponsibility when you found out about them not significant time after and you could have had your co-workers petition for action to be taken by the company. I do not think you have any legal basis to sue especially considering they made you sign a waver saying so and you cannot sue your boss for that unless she harassed you or something of that sort. You should have done what your manager did to you. Good luck anyways.