[ATP]

If there wasn't enough postage on it, it's likely being held at his local post office and payment due for the amount needed. They usually will stick a small note in his mailbox to let him know the amount due and where it is. As far as refund goes, insurance is there to protect the seller more so than the buyer, so yes the obligation to full refund is on the seller if the package never arrives. I bet it is at his local post office though awaiting payment.