I had a similar experience with Sixt in Germany.
They seem to make their profits by grossly overchargin on scracthes and dents
I had dents on two side doors and received a bill for 4500. euros . That is about 40% of the total value of the car

FRAUD is the only word I could use to describe it. My insurance eventally took care of it but bad experience.
My company stopped renting from Sixt and everyone who reads this is warned