Lenovo — Notifications not opens & back speaker hang

Website:

www.lenovo.com

I have buy the lenovo k3 note from flipkart and after 6 months phone starts hanging and then it's display colours got fade. So i go to service center and get service but after 2-3 days it's back speaker problem started going service center they changed the speaker but the speaker is vibrating and the problem as it is and the new problem starts there the notification bar is not showing on the screen and the main menu key is not functioning so i go for problems to service center n the other is ready. I m tired of this. So please return my mobilen give my money back.