They need to be giving you curbside service that includes every service from inside, or you need to be calling their superiors about an ADA violation. I read a news story about this, which says the usual procedure is to call the local postmaster and schedule an appointment for curbside/sidewalk service.

Apparently the Post Office is not totally subject to the ADA, because reasons, at least when it comes to their physical architecture of buildings. But they do have to serve you in some way.

They need to be giving you curbside service that includes every service from inside, or you need to be calling their superiors about an ADA violation.