My car has been hit.

My wife was dropping off some letters in the drive up mail box. Across the street from her a less than aware driver in a 20' delivery truck backed into our car. My cherry 78 240D. Not a dent or ding until that moment. The back bumper of the truck hit the rear passenger door. That is where my 3 year old son sits. Pushed the car about a foot. My son is fine. The door buckled in, but you can not tell on the inside of the car. The door even opens and closes just like new. I thought it was pretty amazing given the amount of force it would take to move the car sideways like that. I am just glad my family was driving the Mercedes and not the Saab. Anyway, long story short, The car is getting fixed next week. Everyone is OK. And none of this is going to cost me a cent, other gals fault.