This car rental service charged a $50 "administrative fee" for a late toll payment. I paid toll authorities the fee of two dollars 6 days after passing the toll.  Upon returning the car, the attendant was aware I had had an outstanding toll balance and could've informed me I should pay authorities within two days of crossing the toll point to avoid the $50 toll from authorities, and the double-billing scheme "administrative fee" of $50 charged by Sixt. Through multiple email exchanges with Sixt Customer Service, I learned that the $50 "administrative fee" did not settling an outstanding late toll penalty. This information was not at all made transparent to me from Sixt. I feel it's good practice to be aware of and speak out against any business practice that administers double billing schemes such as I've described, and deceives customers with these tactics. Avoid using Sixt Car Rental services at all costs.