did you pay it?
its common here that unlicensed taxis sit outside stadiums and event venues looking to scam people. it is a big thing here and run by mafia types in the city.
police dont want to deal with it, so its up to the you as the customer to challenge or pay, you find most of these taxi drivers and pretty big hard looking cants, but i do love a challenge sometimes. One guy tried the 2000kc thing with me and got 300kc and lunch voucher thrown at him.... seemed happy, maybe he was hungry, :-)