This sounds like a Post Office issue. If you do not receive it by the time the IRS reopens, I recommend calling them at 800 829 1040.

I recieve ssi an filed thru stimulus registration on apirl 11 2020. I still havent recieved mine an irs says it's still processing.  But same day filed I filed 12 other people stimulus as well they have all recieved theirs via direct deposit or mail. So why havent I recieved mine.