Budget Car Rentals with Hotwire.com

I rented a van for 3 day coming on sept. first second and third but due to spending 300.00 on the van mind u the money was already debit from my account i'm not able to afford the additional 160.00 in gas fee so i called to cancel policy say if u don't use our services we keep ur money anyway with a no return policy i'm out 314.00 what company has the right to keep all of my money if im not able to use their services. please feel free to inform me why other companies charge a fifty dollar cancel fee and hot wire through a agreement with budget allow customers to be out of their money if they are not able to use their merchandise such as their van.something should be considered in the policy agreement between the two parties that the customer shouldn't lose out on all the hard earned money and don't use the se3rvice its a rip off cause i'm out 300.00 bucks.....