Here is Hertz's stated policy for SJO:
If you make a reservation specifying a pick-up location and you do not arrive at the specified pick-up location for the rental within two hours of the specified pick-up time, (or if the location closes before then, by the location's closing time), the reservation will expire.
However if you are arriving by airplane and have provided Hertz with flight details (including airline and flight number), the reservation will be held until two hours after the flight has landed and cleared.
If you are a Hertz Gold Plus Rewards Member, the pick-up period will be extended to three hours in each case.
You can complain to Hertz corporate but Hertz in SJO is not a corporate location. They are an independent licensee which means they are a local Costa Rican company that licenses the Hertz name, reservation system, etc. That's not to say that they have no sway over the licensee, but it's quite limited as compared to a company-owned location.