I think you're probably hosed. I just had an atrocious experience on a rental agreement error (mileage at gate was mis-logged and when returned, a non-sensical entry seems to been have made from the "Trip" reading vs the odometer. Agent with whom I interacted simply lied to me in the face of photographic evidence of the impossibility of the initial mileage and refused to budge on a mileage charge 2x what I could've theoretically driven given my origin and destination.
Hertz is a shady Company that should be avoided if at all possible.