Very worst experience with Fast track in Mid night. Review on Fast Track Taxi

I was coming from Airport to my home in chennai. We booked a fast track cab and instantly we received a message saying, you will get a discount if the cab is without Fast track sticker or with different register number.

SO once we get into the cab we asked the driver about the discount, he said nothing like that, so to confirm we called fast track and inquired about the discount mentioned in the message.

Then suddenly the driver started to shout on us saying he is servicing in midnight so we should appreciate him instead we are complaining about to Fasttrack. He spoke very harshly, so we asked him to stop near a police jeep and we told the issue to police, they warned him to go with as it mentioned in the message. But again that guy spoke unwantedly. When we complained about this to Fast track their response is very worst its like they are providing service for free. This will be my last ride with fast track.