Yes, you can potentially sue the agency for one or both of--Fraud--or materially misrepresenting (i.e. lying about) what they would provide for you; orBreach of contract--violating their agreement as to what they would provide. If you can prove either or both of the above in court, you could potentially recover 1) any expenses you paid out in the meantime which *should* have been covered by insurance; and/or 2) the cost  to buy a new plan on the open market; and/or 3) a refund of what you paid for the incorrect plan.