You may be able to find assistance through your state insurance administration. Call them and explain your situation. They may be able to give you the name of one or more of the smaller insurance companies who do business in the state, and you may be able to find more affordable coverage. Depending upon your lease agreement, you may be in breach of the lease agreement if you do not keep it properly insured, and the lessor may have the right to repossess the vehicle.
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Your lease agreement more than likely requires you to maintain an insurance policy on the vehicle. Therefore if you do not have insurance that means that you are in breach of the contract you signed and they have the right to take the car back. Call around to smaller insurance companies to see if they may be willing to offer you a better quote. Otherwise, you are probably stuck with paying a high premium if you want to keep your car.