Sony India — Lots of problem occurs, within 5 days from purchase date

Address:

Madurai, Tamil Nadu

i bought sony xperia L MOBILE PHONE ON[protected], as the display looks dull & dirty, dim and camera left key button not working properly, phone gets hang up, stamina mode is not working, gets over-heating while using phone continously for about 15 minutes,
i went to sony service centre, ACCEL FRONTLINE MADURAI, they are not responding just there are saying its software problem, & they updated software on[protected], but problem not rectified,
again i went to service centre & they replied the same & once again they changed software,

but problem still now not solved & i am now helpless, i felt much on purchase of sony product as the problem occurs within 5 days & they are not resolving it ..please help me to resolve this problem...
ph.no:-[protected].