help needed 3gs

i put my phone into local shop for unlocking i got it back completely wrecked with scratches and so on he also said it couldnt be switched off or would need him to "re boot it" after lengthy arguement in trying to get my cash back and new cover to replace the nearly new phone he recieved while i got the wreck.my problem is this it wouldnt accept my sim so i thought if i restored it i would get my i phone back to original settings but when i dfu it goes so far then comes up with error your trying to restore it to an earlier version .any help would greatly be apreciated as i cant go back to the shop and i dont know what they used to unlock it /jailbreak with the symptoms it looks like redsnow but what do i know