The main post office near where I work was blocked this morning. They had the mail trucks parked so you could not get into the parking lot and also blocking all the curbside mailboxes. Yes, I know the USPS is claiming they are still working, but in fact that is not the case here.
I suppose you could call the police and see whether they would tow the mail trucks away, since they are parked in “NO PARKING” zones, but I doubt that will happen.