I hope you fought the charges and contacted Hertz to get it reversed. Were they fraudulently charging you for a whole tank or fraction of a gallon?

Hertz has definitely gone downhill a LOT, and their 'customer service' is garbage now. Car rental companies are generally known to try to charge renters for fuel even when they return the car full... this is especially a problem with those 'connected cars' where it transmits the fuel level when you return it, however those are frequently inaccurate and take a while to register full if you just put fuel in... so the gauge in the dash can show full and you have a receipt, but the stupid connected sensor info will still report its down a gallon or more.