score:2
Unfortunately I have found no answer to this, and it's probably unlikely you can call the Thai airport authorities about this. But I can give you my general advice.
Reporting them to the Land Transport Department is the best and most recommended on the web. Plus, they have the authority to probably revoke their license and maybe discuss the matter with the airport. The airport only certifies which taxi driver can drive publicly, but the Land Transport Department deals with everything else. There's a reason why they're called "Land Transport Department" :)
Note that threatening to report them may or may not affect them, as tampered meters are always a problem too, so you can choose if you want to simply get out of the taxi and find another one if they refuse to use the meter or continue if they give up and starting using the meter.