You're saying the decal was sent back? Or you aren't sure? The mail on those has been taking some time. You can get a duplicate decal at a kiosk. https://dmvnv.com/kiosk.htm Also the DMV is going to be closed Saturdays beginning August 15.
Why did it get sent back??
Call them
You'll have to go in on a Saturday for walk-ins. And explain what happened.
Thanks! Your answer is awaiting moderation.