Are you suggesting they meet his demands?
If he demanded they get a shortwave transceiver and listen for contact, absolutely. That's SOP for kidnap scenarios in the Third World, if I understand correctly. But to come back with "Duh, we're stupid, we don't know the way to Radio Shack, can you come into the office and talk to us instead" would be a plain insult, and would probably result in somebody's kid getting killed.
As far as paying a ransom, that's routinely done. Just because we have an advanced law enforcement infrastructure in this country, which makes successful kidnappings rare, doesn't mean it's fiction.
One thing's certain, this professional assassin is dancing circles around Law Enforcement, and the futile search for white vans is becoming embarassing. If there's a way to secretly wire a ransom, and try to catch the perp when they go to collect (wherever in the hell that may be), that would probably be at least as effective at this point.