It WAS your fault my guy, what are you high? You were driving the package car, correct? You nosed-in to a stop, correct? You left the package car to make a delivery and let the PC roll away and hit another car, correct? How is this not your fault. Select a decent parking spot and this whole thing could have been avoided.
Could have been a child walking behind it. Lots of scenarios. I’d say them letting you go without having anything like that happen is a win Chief. See ya when I roll through McDonald’s!