Leasing office sent move-out papers but no refund check — what should I do??

I just got an envelope from my leasing office with all the move-out papers and the statement (which they had already sent via email!!), but there was no refund check inside. 🫣
This is my first time moving out in the U.S., and I’m honestly super worried.

What’s making me extra anxious is that I signed for the registered mail when it arrived, so I’m scared they’ll now claim they “did their part” just because I acknowledged receipt — even though the check was never actually inside the envelope! 😰

I contacted them right away, but the office is closed tomorrow, and I can’t stop thinking about it.

Is it normal for the refund check to arrive separately, or could this be a mistake?
Has anyone experienced something similar before?

Any advice would really help — I’m FREAKING OUT a bit!!! 😬