Melbourne Taxi Experience

I got back from a tour that dropped me off at the Mail Exchange Hotel around 11:40 PM. I decided to take a taxi back to Melbourne Port to the cruise ship. Google map showed the distance is about 4 KM. There are some taxis waiting in front of the hotel. I looked it up on Melbourne city taxi fare, and it showed 15 AUS for night time fare for 4 KM. After I got in the taxi, the driver started driving without turning on the meter. I asked him why the meter wasn't on. He said because he only charges flat fee, and it would be 39 AUS. I told him that was not the cost it showed on taxi fare website published by the city. He then pulled over in the middle of nowhere, and claimed that if I did not pay right away, he would take me to the police station. I did not feel like arguing with him, and just paid with credit card to dispute with credit card company later. Beware if you take a taxi in Melbourne at night.