SonyEricsson — problems with update

Address:

Maharashtra

I bought a Sonyericsson Xperia Arc LT15i on 05 Jan 2012. No problem till 05 Jun 2012when prompt came for update. Update was successful with Version 4.1.B.0.431. The prompt then said remove back cover, remove battery and replace. Restart phone. On restart instead of Sonyericsson logo only 'SONY' logo came on followed by a icon not given in the guide which showed 'Phone dead'. Went back to dealer and phone sent to service centre at Shivajinagar, Pune, India. Phone returned with old sonyericsson software loaded. Phonebook saved on memory card was lost, fortunately it was saved on google. Now phone would not accept tel nos saved by create account in the phone memory. Dealer asked me to connect phone to google and synchronise. When phone connected to computer a prompt'Update to latest software came again. So clicked on imstall and process started again. The new logo for PC companion was now blue instead of green as earlier. Update was stopped because of file error as stated on screen. Did not touch the phone because on restart again the same problem recurred and 'Phone dead', prompt appeared on phone screen. returned the phone to dealer for service centre.
KINDLY LET ME KNOW WHAT IS THE PROBLEM, WHY IS THE PHONE MISBEHAVING WHEN UPDATE IS EXERCISED.
SHOULD I STOP UPDATES??? THEN WHAT IS THE USE OF PC COMPANION ET AL?
WHY DOES THE MEMORY CARD NOT SAVE ALL THE PHONE NOS WHEN BACK UP IS EXERCISED EACH TIME I PUT IN A NEW NO.
I AM FED UP OF LOSING THE PHONE BOOK AND MY DOWNLOADED SOFTWARE EACH TIME.
EVEN MY PHOTOS ARE ALL REARRANGED, WHY?
PLEASE PLEASE HELP ME TO RESOLVE THESE ISSUES IMMEDIATELY OR ELSE REPLACE THE INSTRUMENT IF IT IS AT FAULT.