Sony Ericsson — Set not charging

sir,
i m Dr. Abhijeet from dhanbad(jharkhand)
I purchased W760i from patna in october 2008.my first problem occured in december 2008.the set was not charging nor could i listen music in headphones and there was an error message when i tried to connect net with my laptop.in short system connector of the set was not working properly.
i went to GRAPHLINE CARE ( 412, ashina plaza, budh marg, patna-1 ).they booked my complain with complain id-seo[protected] on 4 jan 2009 and retured the next day telling that problem was solved.but all problems reappeared within 2 days but i had returned back to dhanbad.
for repairing purpose i again went to patna in february 2009 and again they booked my complain and said that they will send the set to chennai.i got back my set in april 2009.in this process they lost the walkman shortcut button and assured me that they will replace it.i went 3 times to patna but always they had an excuse that the button was not available.the button is missing till now.
now from last month same problem has appeared and along with that insert sim message comes on screen spontaneously for which i have to switch off the set and remove the battery and then restart the phone.this happens daily 3-4 times.
due to all these i m suffering a lots of mental tension and financial also as each time i have to go to patna to dhanbad.there's a lots of wastage of time.
so i want a permanent solution to this or please get my set replacad by another one.
set details:
Make- SONY ERICSSON
iemi no.-[protected]
model no.-w760i
purchase date-20 oct, 2008.