If there were witnesses and a type rating was promised it would seem that you might have a legal leg to stand on...especially with a (non-federal) government agency where they have to be more transparent than your typical fly-by-night 135 outfit.
It may come down to whether the CP actually promised you something and you made it clear that his promise was a condition of your coming to work. Verbal contracts are generally binding, the problem is proving it...but if you have five witness who are government employees they probably won't commit perjury. Too many witnesses.
If the boss simply described your "likely" career progression, well too bad things change sometimes.
But this isn't really a fight you can win...even if you get a type out of the deal you'll either have a toxic work environment or an ex-boss who won't give you a good recommendation.
If the pay and bennies are good maybe you'll eventually get to do more flying? Also it's the nature of government work that you'll be in the office if you're not on some kind of flight schedule...they get in big trouble if they pay people to stay home.