I shipped a package from Copenhagen, Denmark, which was last recorded entering the ISC at JFK in July. There is no contact number for a customer to contact Atlanta, where a rep has suggested my package was sent to after being damaged and to be auctioned off. We tried contacting anybody within 90 days before the next auction day but the numbers and reps send us in circles. I went to investigate the situation at ISC and bumped into a Postal Inspector, who mentioned that 8 postal workers were arrested in the past 3 months for stealing packages. What would your advice be to open a lawsuit?
First exhaust your remedies with the USPS. They probably won't be able to do much if you didn't register or insure the package.
Then check your remedies, if any, from whoever sent you the package to see whether the shipper assumed any risk of loss in transmit. if you shipped this yourself, and didn't sent it via a trackable method of delivery such as International FedEx, you may be out of luck.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.