Nokia5233
Some time sinktouch is not working

In nokia care i give this problem 4 times but they could not slove it.

1st-7-04-10 job sheet no- 297504886/100407/31

2nd-- 12-4-10 job sheet no-297504886/100410/40

3rd-- 5-05-10 job sheet no--297504886/100505/23

4th-- 5-05-10 job sheet no--297504886/100505/23

i am fhedup in this problem plz slove this problem quickly or give me new nokia5233 handset