I rented a car over the summer. Few weeks after the rental was complete, Sixt charged me >$250 for a special cleaning fee, because the car had a "heavy smell of cigarettes", which was of course not true. When we rented the car, it had a very light smell of cigarettes, but because it was late at night and because it was very insignificant we did not think much about it. When we returned the car, we were told that everything is fine (and final bill reflects that). Long story short, my bank blocked the charge as invalid, but Sixt sent me a letter saying that they dont care and they will send the bill to collections if I dont pay. What kind of racketeering is that? Crazy.
I tried reaching customer service many times (via phone and email), but noone responds to my messages (including email address that someone has previously responded with in some of the reviews below).
p.s. neither myself nor any of my passengers smoke.