I broke down & (guiltily) called F.I.R.E. The woman who answered the phone was incredibly nice. She explained that the post office holds the boxes for them, and someone picks them up a couple of times a week. This means that they don't always get scanned. She didn't have my packing list in her pile, but said she would call me back at the end of the week to let me know if they'd received it. I thanked her profusely for that (and asked several times if she was really ok w/that, since they're so busy).
And, on a really
happy note, they've surpassed last year's total!!!
Edited to add:
Stacy just called me, and my box is there! She is made of awesome!