Xseries :: X3-02 Touch Screen Not Working?

I bought my Nokia X3-02 in 2011. It worked well for 11 months and in the 12th month, its touchscreen stopped working. It was under warranty so I went to Nokia service centre and they changed the Touch screen Digitizer.It worked well for few days and meanwhile its warranty expired. Now it has the same problem and the touch screen doesn't work at all. So, I put the phone back to the phone and started using my other phone.after 2-3 days, I thought that I should take the phone to the service centre, so removed the batter and inserted the SIM card. I started the phone and touch screen was working fine. I thought, I am lucky as the touch screen is working now. But after few hours probably 3-4, the touch screen stopped working again. Quite weird behaviour.So, if i put the phone to off for around 1 day and starts using it again then the touch works and after few hours it stops working again. I went to service centre again and they said, they would firstly change the touch screen ( price INR 1500) and after that they could comment on the phone's behaviour.

UPDATE: I have updated the phone firmware to latest one. Touch works even after 5 hours but not the exact point of contact.. When i try to press Menu, it always activates the Address/exit button, so the wherever you touch it activates the right side of the area.