Refused to pay for my vehicle.

I have paid my premium faithfully for over 18months without fail. I had a call from one of Innovation Group consultants whom I advised that my engine light was on. He advised i take it to the dealer or RMI approved shop of my choice. I went ahead and took my car to the dealer who diagnosed the issue and made a claim. I have an engine and electronics warranty. To my surprise Innovation Group has refused to pay. I have asked them now that they made me take my car to Mercedes benz can they get it out as they won't release my car for free they have refused that too. I am stuck dont know what to do as I feel cheated. I wonder what I have been paying for all this while. I really regret getting a warranty with this company. Now I am in debt and they are still deducting my money without any help. Sies....