If your car was a total loss, you have concluded your contract and would have to pay the premium in full. Your argument is that you have not had the benefit of the remaining months. Some insurers accept the argument and will put another car on the policy. Others do not. If the insurer is receptive to it, you can ask them to freeze the policy till you find another car - they may agree, but as advised above, the contract ended at the point the car was a total loss, you are not entitled to it.