I joined FlyerTalk just to respond to this thread. We had nearly the exact same issue with Sixt Croatia, renting from Dubrovnik. They gave us an absolute beater of a car--not just scratches but literal dents everywhere and bald tires. We return the car and a week later just happened to check our credit card statement. They charged us $700. Upon investigation, the charges were for insurance we never agreed to and a scratch on the bottom right bumper "5cm in length down to primer." The scratch cost nearly $500. We couldn't believe it. There were no scratches from us on that car when we returned it. Went through Chase, who after several weeks of investigation, agreed we weren't liable and removed the charges. Yet, Sixt Croatia continues to come after us for the charges. We just got a notice from a Collections Agency. We actually contacted a lawyer here in the States but we can't decide if it's worth continuing to fight this, paying it, or just ignoring it. Sigh. I will, I swear to all things holy, NEVER rent from Sixt again. What a scam of a company.