help me pls
(paiseh if this question have been asked numerous time)

i juz got my iphone 3gs from my sis (she got spare unit but it has been used) which she bought it in bangkok.

i'm such a noob. i go put my sim card in n they load the numbers but can't see names.
so i went into a shop 2 ask 4 help n that guy reformat my phone.
jitao LOCKED!

he say i can't do anything with it anymore

anybody can help me w this?

pls pls plsss!