Revhefty, the US Customs and Border Protection Service has a web-site that may help you locate your property. www.cbp.com
and the telephone # 877-CBP-5511.
The cbp web-site has a section that you can ask a question. The web-site has alot of information that may be helpful to you with your problem.
Sometimes your local US Congress representative office may assist you in getting the information you need.
If you are in Madrid the United States Embassy may be of assistance. The embassy is at Serrano 75, telephone 915-872-200.
Revhefty please keep this site informed on the progress of your situation. Thanks