Nokia 7210 supernova
Switch off and hanging

Dear sir,

i bought nokia 7210 supernova set 12 months ago.right from that day my mobile used to switch off persistently.i went too nokia care centre 4 times.and they said that they should install a new software.but after installing new software for 4 times my mobile keeps on switching off.and all messages and photos gets deleted.can u please replace my mobile.or else what should i do to solve this problem.and my warranty period is yet to finish within 5 days