Hertz Rent A Car

I booked and paid for a 5PM reservation online. At 2:30PM, this branch calls me up and asks me if I can come early. I can’t, because I’m at work. Odd, but ok. At 4PM, ONE HOUR before I’m due to pick up the car, Hertz calls me again and tells me they don’t have a car at all, and asks me if I can come by the next day. Obviously, that wouldn’t work for me. Upon my arrival at 5PM, they’ve scrounged up a huge van for me to rent (instead of the economy car I’ve reserved). Mildly annoying, and will cost me extra gas money, but at this point, I’m just happy they’ve solved the problem.
The next day, another employee calls me up and accuses me of STEALING THE VAN and THREATENS ME WITH ARREST if I don’t turn around and drive back right then and there, nevermind that I am 4 hours away at this point, that I paid in advance online and that I have a signed receipt in my hand!!! Unbelievable. Dear Hertz, I’d like a full refund, and this is in regards to reservation #G9320105823. I’m still waiting.
Edited to add: Hertz customer service tells me only the branch can issue me a refund; The branch tells me only customer service can issue me a refund. Frustrated.