IPHONE 4 - anyone know if this is network problem or phone itself problem

biggebruv

to start
guys at o2 said its not blacklisted
bought second hand iphone
tried sim activation wouldt work
so i JBed it with green poison redsn0w
baseband 30.10.01 cant be unlocked thats fine because im using o2 which is what network the phone was linked too apple said
synced iphone with itunes that all went well and its done

then

theres no carrier
in settings it says

carrier - not available

apple said its locked to o2 PAYG sim will work
rang o2 they said sims set up everythings working
the sim works in other phone

so i

put o2 sim in and no bars show up noting
theres no carrier options in settings

tried switching on/off/airplane mode
restarting,rebooting,restoreing
and still theres no bars with o2 sim

im thinking off sending it into a repair shop but does anyone think this is a iphone problem or network problem

guil

ya dont have to keep making new threads about this, did apple say it was o2 ireland, are ya sure its not o2 uk
if its uk, an irish sim wont work in it