Is Sixt able to inflict any more damage on me even though the bail has already been refunded?

Hey rented a car at sixt on the weekend when I wanted to leave it again I discovered a scratcher in the bumper which I certainly didn’t cause because I didn’t drive anywhere at the return I also said nothing about the scratch because they want to attach to me afterwards now you can transfer the deposit back sixt now still claim damages and I get a letter or is the thing with refund of the deposit – Did you eat?