Dollar Rent-a-car Overcharged fuel fill-up Los Angeles, California

I rented a full-size car through Dollar (I think it was a Ford Escape) for $97 for three days from 31 Aug - Sep 3.  I took the option of filling it up with gas, knowing they would charge me $9 a gallon if it wasn't full.  I was tight on time after dropping my fiancee off to catch her flight.  The tank showed nearly half full.  I did the math and figured it would be about 10 gallons max, so I decided I would have to eat the $90 fuel charge.  Except I just saw they charge my card $288!  That means they charged me $191 for the gas they put in.  What a bunch of jerks.