Take your car to 3S dealer and ask for warranty manager
Is it due to seat making squeaky noise? I drove Mehran for 4 months while waiting for my Altis and my right leg started hurting like so much that I had to see artho specialist and had been on medication and physiotherapy (self exercises for month).
As soon as I started driver Corolla it felt so soothing to pain and still I enjoy the comfort and coziness of the original seat (no rexin or fabric seat cover installed).
There could be other reasons for your backache
According to the people who have bought GLi AT, they say it is not under powered. But changing gears on AT!!!!! then what's the need of AT?