Taxi scam with rigged taximeter

Just got scammed using the airport taxi. Guy tried charging me 1800 for a 30km drive.

First time I got here so I tried looking online for "how much per km" and figured I was paying 10 times more.

Not knowing what to do he demanded payment at 500 minimum which I paid in order to get on with life.

Thing is, he was using a rigged meter.