Unfortunately it doesn't seem to be a breach-of-contract issue. You were duped by the overseas employment agency with a false contract. That isn't necessarily the fault of the employer here who issues the real contract. The problem is that you weren't able to see or agree to the real contract before arriving here. I suspect that the employment agency is back in your home country. That's who you have your problem with. Pursuing the employer here who may (or may not) have had anything to do with the deception seems to be a futile gesture. My suggestion is that you talk with your employer here and tell him/her that you were mislead and see what can be done. You could also warn people back home.
Mandi