How can I find out if my card was returned to USCIS or lost in the mail?

You can find out if your card was returned to the USCIS by calling the National Customer Service Center at 1-800-375-5283. Cards that were returned to the USCIS are not considered “lost in the mail.” CITATION.3b) http://www.uscis.gov/sites/default/files/files/form/i-90instr.pdf