U-Haul Neighborhood Dealer

I rented a cargo van from here and dropped it off after hours. From their U-haul office/shop in Collinsville, I went to Edwardsville, to downtown St. Louis then back to Collinsville to drop it off; a 48 mile trip. When paying for the van upfront, I pre-calculated a 50 mile round trip. I received a second charge on my card for just under $20 so I gave them a call; they said I drove a total of 75 miles. Needless to say I crunched some numbers. I topped it off with $10.71 of fuel at $3.59/gal which is three gallons. Forty-eight miles driven divided by three gallons is 16 mpg which is what that make/model van gets according to their corporate office (yes I called them too). According to cooperate, there is no way to dispute mileage. This tells me that there are some dishonest people working at this location. They charged me "mileage" and put $20 of fuel in their car on my dime. I understand it's only $20 but it's unethical. RENT ELSEWHERE.