Car accident claim rejection.

My mother had insurance on a car I regularly drive and had informed the insurance that I'm the regular driver. I got into an accident last year with the car and they declined the claim stating that she didn't inform them that I was the regular driver even though four months prior to the accident I had claimed windscreen damage and also stated on record that I'm the regular driver and my claim was approved. But when my mother claimed for the accident, she was rejected. Now it's been month of going back and forth with ombudsman because they are taking so long to attend to the case.