Phone does not work properly

I have a soni ericssion w700i mobile last year. i want to listion a song but it;s sound is low qualiti whenever i do voluam full.when i am in a call after 1-2 minits a can;t haer clearly voice are hearin normal to law & low.whenever i attach earphone & listion music than if anyone call me song is stoped but my phone is hangd i con;t listion caller not song.in stand by time battary work only 12 hour. i listion music the low battary indicate me after 1 hour. i am in big confused what can i do.