signed check that was supposed to go to night drop at bank, accidentally put in mailbox at post office?

today is thursday and on tuesday night my dad asked me to put his check from work in the night drop box at the bank, it was in an envelope marked "deposit", i wasnt thinking because i had more than one errand to run, and i accidentally put it in the post office big blue mailbox, the check is like for 3000 and it is SIGNED by him. what should i do?

Call the post office. It can’t go anywhere. I’m sure the postal worker brought it back to the office.