Let me know how Hertz works out for you. When you do as you wish at Hertz and get charged where will you go then?
YOU SOUND LIKE A DYKWIA KIND OF PERSON WHO THINKS YOU ARE ENTITLED TO DO AS YOU WISH.
When do you take responsibility for any part of the mess you got yourself into?
You do not check before acting and this carries over into YOUR customer service. You got billed more than expected because of your action or lack of following direction. You never verified your bill and then you over billed your client without verifying the charges you billed him for. Poor business practices on your part.
How about you do your job from now on.