It was for (cherry hill, NJ [PHLE06]), Oct. 30-Nov.3. Pickup and dropoff at noon.
I called customer service, and they confirmed that indeed all cars of all classes were sold out for those dates, however, that doesn't explain why trying random dates 6-12 months from now also resulted in 'no cars' at that site.
However, you bring up a good point travelismylife, I think they may be merging with Alamo at that rental location, not sure if it's going to be purely Alamo or purely National.
I'm going to try on a different computer.