Car rental frustration

So I'm trying to find out rates, what kind of car I need, etc for a cross-country trip.

You'd think this would be easy enough, especially given the fact that we're able (in THEORY) to investigate things like this online, and to call local dealerships, but no.

Thus far I've called two of the major chains who have locations here, and although both claim to be open until 6:00 PM, and it was only 4:00 PM when i started calling, before peak hours of this holiday weekend, NEITHER of them have answered to answer my questions!

BOTH said they were closed, and to call back during normal business hours, even those this is WELL BEFORE normal business hours. I've never before countered this, and now have no idea what their actual business hours are, because they're not what they state they are.

Has anyone else here encountered this, and have any suggestions of what to do?

This is my first time renting a car, first time making a long-distance trip, too. It never occurred to me that a company would state they were open from X to X, and not be. Let alone TWO of them, on which many people depend.