Hertz screwed up applying my earned rewards points on a rental and charged me $400. I was on chat with their customer support while booking the rental and spec

Hertz screwed up applying my earned rewards points on a rental and charged me $400. I was on chat with their customer support while booking the rental and specifically mentioned that I wanted to use my rewards points for the rental and followed their guidance. Their booking system was crap and would not show rewards being applied half the time. I took screenshots and saved all chat transcripts. When I saw that they finally charged me full amount upon returning the car, I sent them all the proofs I had that this rental was supposed to come out of my rewards points. Upon my escalation they reviewed it twice and they refused to reverse the charge and said I should consider their response "final". I gave up and ate the $400 charge. Wish I had more patience and time to fight it.