Terrible experience

I paid for Toyota Innova or similar car but they downgraded to a Malaysia made 4 door sedan. The size was much smaller and the staff rejected to change a similar car. I had no choice but to take the downgraded car. The Bluetooth audio took us 40 min and not able to connect my iPhone for GPS and audio. Most car rental companies rent the car with full tank of gas while this one left only less than half tank and the staff said to return the car with 3 bars. How could I return the car with exact measurement for 3 bars. Without any choice I had to fill up the tank almost full to benefit the next renter because there was quite a distance between KL city center and the airport.