Uscis Chicago Address USCIS Chicago Lockbox Open On SUNDAY?

USCIS chicago lockbox open on SUNDAY? - uscis chicago address

Send your application (I-130, I-485, I-864, etc.) on Friday via USPS Priority w / registered mail ... Track your package today and said it was delivered 9pm Sunday 30th I do not think the USPS deliver something, on Sunday ...
Is it possible to receive requests on Sundays? I worry a little: (