Had a real bad taxi experience on last trip to bangkok. Stayed in Novotel PloenChit Hotel for 5 days and 4 night. On last day of trip, requested hotel staff (bell boy) to get a metered cab to airport but was instead directed to a cab which wanted to charge a flat rate of 500. So requested bell boy to get another cab. The next cab agreed to charge by meter but while loading the luggages, noticed the cab driver exchanging eye signals with the bell boy. The taxi experience was a nightmare. After boarding, the driver refused to on the meter and then gave all sorts of excuses. He reluctantly on the meter after we said we wanted to get off. But he demanded service fee of additioal 50 baht. On the highway, I noticed the driver intentionally took a turn when the airport sign show going straight. Nothing much can be done as we are already on the highway and unable to get off. The total fare came up to more than 500 baht (including toll charge). A 30 min trip ended up more than 1 hr 15min. Had we not left the hotel early, we would have missed the flight.Can fellow forummers advice if it is ok to request for metered cab even if we board from hotel? Does anyone have similar experience to share? Is there anyway to lodge a complain against the taxi driver?