My Apple i-phone4 screen sensor was faulty, and giving serious problems after ~ 9 months of purchase. So far, I have taken the phone 4 times to the Apple authorized service provider in Aundh, Pune. They reset and returned it to me the first time. Then, replaced it - but the same problem kept on even on the replaced piece. After that, I have taken the phone to them twice again - and they keep reseting and giving it back to me despite the persisting problem. Their claim - they could not make the problem recur.