US Post Office

I’ve been coming here for years but yesterday was the worst I’ve been treated. I came there to mail two cards. One had everything filled out and the stamp was already on it. The other one needed a stamp and needed a zip code for the addressee.
I didn’t wait too long in line. However, when I asked for the zip code, I was told by the clerk that «this is a finance station, not a post office» and «I can’t look up the zip code».
First of all, she was lying because I have had clerks in this post office look up a zip code. Second of all, on the exterior of the building it says «post office», nothing about a finance station. If they don’t want to act like a post office, don’t claim you’re a post office. I had to go home to look up the zip code and mail the card a day later.