They have been doing this for a year now and charging a flat rate of 25tl for the Calis area, totaly not on. We never use them now and always call the taxis by the state hospital.
My daughter used them 2 weeks ago to get a taxi to the Sunday market from the taxi boat office. Once they got in the taxi he turned his meter off, my daughter who speaks Turkish told him in no uncertain terms to put it back on again, which he reluctantly did and then proceeded to drive like a lunatic to their destination. The fare came to 14tl!
She gave him a 20tl note and where she would have left the rest as a tip she waited for her change...