That's awful. I usually use Priceline and haven’t had any serious issues, often the cheap schitbox I reserved isn’t there so they give me a bigger car for the same price as what I reserved.
Those are some crazy high prices. Rental car prices swing wildly depending on supply and demand, that’s why you always want to book it in advance. Which I know you did.
I was in Minneapolis last summer and the whole city was out of cars. I went to a local Enterprise in my old neighborhood and pleaded w them, (same thing where I’d reserved a car online an hour before but they didn’t have it). Eventually, the young guy says, “I don’t have a single vehicle here except for a pickup truck!”
Which one? He points out a new F-250 aluminum Super Duty 4x4, I told him that I like trucks but that thing is probably big $$. He tells me that he’ll give it to me for the same price as the $8.00 car I reserved and throw in the half tank of fuel in it.
SOLD! 
I wrote up a good review on the truck somewhere on this board.