Hertz Car Rental - Washington DC Dulles International Airport - IAD - Virginia - USA

Staff ill informed on car features and rental agreements. We ordered and paid for a PREMIUM 8 seater Yukon XL standard GPS. We had to travel all way to Dulles int to pick it up with was $97 shuttle for 6 of us.
Arrived with our 6 large suitcase & 6 people to be told it didn't have GPS. They then gave us a 7 seater minivan with GPS. Then charged us $65 upgrade per day for our 7 day hire.
We were not happy but staff told us it's supply & demand. That equates to I can charge you what I like cause you need this car.
We had already wasted one morning of our 7 day Roadtrip.
The car boot remote stopped in Wilmington NC. For an hour we tried to get it to work the whole hydraulics wouldn't work.
We rang roadside assistance which we paid extra for, they decided to send a tow truck take it to Wilmington airport and then they called two taxies which hurtz hadn't arranged to pay (contrary to what they told us) to take us to Southport (which was 45mins) for a new at which was not there when we arrived as they did not get back to them in relation to our supposed car. We then had to wait 3 hours for the vehicle to arrive which ended up just being the original car we had. So all up it took 5 hours for the issues to be resolved so as a result we lost that day of our holiday in Wilmington. We had also been told in these dealings by three independent hurtz agents that they could not understand (nor did they think it was appropriate) that we were charged an additional $455 US or $568 Australian dollars for an upgrade which was actually a downgrade in car. But none of these agents had the authority to change this. The only person who did have the authority, the Washington, D.C. Manager that we could speak to, when we rang he said he would investigate and get back to us and that is yet to happen we are still awaiting his call.