SonyEricsson k850 Problem !! Plz HELP!!!

hi everyone am a new to this forum.
i realy need help with my sonyericsson k850 . my friend is a taxi driver and he found this phone uder hes sit and he gaved it to me Caz a didn't have a phone and he told me that the phone is locked to 3 network as it says on the back of the phone.
a tried to put on a sim card but it says insert usim a don't know what that is ?? when a tryi to put on a 3 sim the phone starts up but it would say on the top that's the sim in inactive but the sim worked in Otha phones but not this one.

people told me that the person who lost this phone has contacted the network provider and blocked it . i just wanted to know that is there anything that a can do to unlock or unblock this phone ? plz help me a have downloaded a program called xs++ and this is what it gaved me a dont know what to do with it plz plz help me a realy need this phone
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22:56:49| Profiling SEMC phone...
22:56:49| Platform: DB3150
22:56:49| OTP CID: 52
22:56:49| EROM CID: 52
22:56:49| EROM Color: Red
22:56:49| IMEI: 35182902xxxxxx
22:56:49| Phone ID: K850
22:56:49| Region: HUTCH-WORLD
22:56:49| CDA: 1202-9023 R12A
22:56:49| Firmware Version: R1EA037
22:56:49| EROM: 1200-4341 SEMCBOOT R6A008

thank you very much.