@jasmine fu I called usps for redelivery. They promised to send it within 3 days, and that didn't happened. I emailed CGFNS and they assured me that USPS will deliver the letter to them. After a month of waiting, CGFNS emailed me saying they finally received my documents.
In USPS tracking history, my docs are still awaiting for pick up. I think USPS is not updating their system.