Sony ericsson F305
New phone not working

I have bought a sony ericsson phone model no F305 in Feb and its not working from pass 3 month. i have compalined to the service centre and they retuned the phone after 45 days but still its not working the condition of the phone is even worse.

kindly help me in getting my phone replaced as its under granetee.

regards

Astha Soni

9811338455