Tailgate Hinge problems of the 2004 Nissan Murano

I put the back tailgate up in my 2004 Nissan Murano to put my granddaughters' belongings in to take them home. I walked to the back seat area to put something in the back seat, when I heard a huge whooshing sound and suddenly the entire door slammed down. Luckily I wasn't near it or I could have been killed. The door is very heavy and it slammed down with quite a force. There was a strong smell of a vaporized nature in the car. Now the door is very difficult to open and requires both hands to do so. Evidently one of the hydraulic struts went out. This poses a significant danger to anyone nearby. I have called the dealer and am taking it in today. They were very non-committal about it being something they would repair without cost. They did say it was a very rare occurrence. I am very concerned about this incident and want to report it. If others are not aware, there could be a very serious accident. I am concerned about my own safety as well.