Alex,
I think your friend's best bet would be to return it back to the seller and have them explain why it's not getting a network signal and replace the device if they can't get it working.
If it wasn't getting a network signal when the device was originally purchased, then you're not likely to get it working again without the carrier's assistance (unless there was something done that could account for the loss of the network signal since the purchase--in which case you'd need to tell us what that was).
Best of luck!