Sony Ericssion F305 Handset — regarding repair and service

Sir,
i had purchased new handset F305 on 19 dec 2008 . as i purchased set it has 4 problems.
1. as cal connected display goes black and screen becomes dotted.
2.head speaker has burst sound
3. as i listen music after sometime it speakers gives pppppppppppppppppp sound. and sets hangs.
4. set hangs constantly .
as i gone 2 show it to service center they just formatted my set nothing else they given .
plz look after my problem.

Sir,
i had purchased new handset F305 on 19 dec 2008 . as i purchased set it has 4 problems.
1. as cal connected display goes black and screen becomes dotted.
2.head speaker has burst sound
3. as i listen music after sometime it speakers gives pppppppppppppppppp sound. and sets hangs.
4. set hangs constantly .
as i gone 2 show it to service center they just formatted my set nothing else they given .
plz look after my problem.

my f305 phone has equiliser problem i.e what we set settings of particular song it changes when song changes.so please look after it