I had a package for Israel - it got sent to Illinois when the Royal Mail misinterpreted the international country code "IL". It came back to me about 3 months later and I resent it to the buyer, so eventually he was happy.
A couple of years ago I had one tracked to the US. Tracking showed it handed over to the Customs people at JFK and thereafter, disappeared. Customs refused to acknowledge receipt, Royal Mail refused refund as it had left their control. £200 coin lost.