So, let me see if I understand this correctly...
First, you wait until 4PM to get to the Post Office? I mean, that's not the time that most people get off work? Hmm OK..
Second, you should have researched and had your stuff filled out before you inconvenienced everyone else in line. It's not their fault you don't have the internet.. Oh, wait.
Third, obviously they aren't going to send something over night and risk it getting "misplaced." Obviously they would want a signature confirmation. Standard practice..
So, if I understand correctly.. You procrastinated in getting to the Post Office, you didn't check online to see what your options were and you spent too much money?
Sounds like you're the one at fault here.