They were all nice when I got there and told me that for the discounted I asked for I would only need a receipt from the place I was staying. When I got back (with the receipt) the people there were extremely rude and after I've insisted for a very long time one of them called their supervisor who told me that I needed to get a stamp from the place. I went back, got the stamp and could only get the discount for one of the cars (there were two). One they had already charged the credit card and told there was no way to cancel it (while it's obvious that it's a simple transaction and I could even see myself how it could be done in their system).
I hated how they simply didn't care, wanted their money or they wouldn't give back the car and were all they way rude. There are many options in NYC, don't use this one.