I was parked beside another vehicle at the rubbish tip. I opened my back door and took out a rubbish bin to empty. When I turned around to go back to my vehicle, the vehicle beside me began to drive away. The trailer attached to the other vehicle hit my open back door bending it forward. My car insurance company is saying I am at fault for leaving my car door open. They making me pay the excess for repairs. I feel it is the other person's fault, but they are saying I created the obstacle.