The last 2 times I have had a reservation for a rental car (Arizona and Tennessee) when my flight arrived...there were no cars. In one case it was hours, in the other they said it would be a day or two. What's up with the rental reservation business?
This is really not good, but I can advise you to use https://rental24h.com/
This is a very good booking service and all the car rental providers on this site are trusted and reliable!