Car was fine and service at the counter was good t...

Car was fine and service at the counter was good too. However, I was unaware of this regulation at the time, but prepaid fuel IS NOT authorized for rentals when you're on military orders. Long story short, I'm eating $55 out of my pocket for using 3 gallons of gas. Tried calling customer service to change charges from pre-paid to whatever the steep price is for refueling a non-full tank upon return (at least that would be authorized for reimbursement), but they wouldn't do it.

EDIT: After more communication, everything was worked out. The customer service on the phone wasn't helpful, but the agent at the counter was the one who straightened things out.