CANNOT POWER ON WITH BATTERY EVEN WITHOUT MEMORYCARD

This is Shanthi.S.I purchased ur sonyericsson W810i model on 27th january 2008 from The mobile store, R.S puram, Coimbatore, TAMIL NADU.Now a problem arouse with the set.it cannot power on with battery even without memory card.it is hardly 3 months, i purchased the mobile and now it is in theservice station.i am highly dissatisfied with the model...i dont know whether it is a manufactering defect in this particular set or the model itself is a failure as many people say..anyway...i wish to get some explanation from you regarding this...i purchased the set only for the name SONY...but the set dint speak for the name..really sorry to say this...please give me a reply to my query besides your busy schedule.i also want to know whether i can replace my set with another sonyericsson (Satisfied)model as still i have the warranty period...

expecting reply...
S.Shanthi.