What can I do, being on a Tenure-track position and noticing that the promised start-up package, course release and ... were just false promises? This fall I started a tenure track position. They offered me a very good start-up package. Half of it was state money for buying equipment and the other half was for course release, research assistants, travel and etc. Also I had a promise for spouse support and that had huge impact on accepting the offer (unfortunately this one was not written!).
Now, I see that the only thing I can use is the state money which is more than enough. However, the equipment is not the only thing I need. Obviously, I need students for my research too. It's my second semester and they  have not even sent me my written contact yet. Their false promises have put me and my family in a very difficult situation.
What can I do now? What are my rights? Obviously, I am not planning to stay here. But cannot leave off without doing anything. I do not want other families go through the same situation as me! Other faculty members have almost same issues but no hope for any change.
Note: for the start-package I have an email as proof. Also, initially, the university was required to pay equal amount as state money to new faculties.
My strong advice is that you take an offer from a better school and just do what is needed to get through the year as best you can. If the place is as bad as this then you, with little institutional power behind you, aren't going to make a difference. You will be stomped like a bug. I was once in a bad situation (perhaps not this bad) and went for the door by the shortest route possible, simply saying goodby to the insanity. It worked out fine. As in your case, I wasn't going to get anything from any other action.
In particular don't say things that might come back to negatively affect your own career. Suing them might be an option, but it requires a hard talk with a lawyer first and threatening it isn't going to get you a positive outcome.
I realize this is hard advice to take, but you have a good option and you don't want to do things that antagonize people and that will cause blow-back on yourself.
You are fortunate to have a good option. Take it. Others aren't so lucky.