Front Air Bag Sensor Control problems of the 2012 Nissan Sentra

I have a 2012 Nissan Sentra and the curtain air bags and seat air bags deployed when the driver's door of the vehicle was slammed. The car was not in motion but the key was in the ignition. Took it to a dealer and was told that they do not think this would be covered by warranty to contact my insurance company. The vehicle was involved in a rear accident 3 months prior but no air bags deployed only the trunk was smashed in. I was also told that the repairs to the trunk could have caused a malfunction. The car was only examined at the dealership I was told that Nissan corporate office was involved but never was called nor has the car been inspected by a professional. This too me is very unsafe and inconsiderate of Nissan to ignore this matter. What if the car was in motion what type of accident or injury this would have caused. I feel they should have at least inspected the car by a professional to make sure this was not a sensor issue and to confirm that it not their fault.