Dear Bob, your best defense against any call showing a name or number you do not recognize is not to answer it. Caller ID is one of the best investments I ever made in paying for local phone service.
Now, about mystery phone calls from area code 504. I live in area code 504, and have noted an increase in the number of reported (to 800notes, whocalled.us and others) bogus calls from there. I did a reverse number check for this number through whocalled.us, and learned that this cell phone call presumably came from a suburban neighborhood called Mid-City (although the number could have been spoofed). The call came from what is apparently the intersection of Orleans Avenue and St. Ann Street, which puts it directly in an area that you drive through with your windows rolled up, and through which you don't walk, especially at night. (You might want to read up on Storyville; this area has some claim to being a latter day edition of that unique neighborhood a century ago.)
Some very nice people live there, too, but then there are the others....
My opinion is that if you live in the metro New Orleans area, and you got a call from area 504, this could very well be a wrong number. When I returned from being an exile from the city after Katrina, in 2007, the phone company would not give me back my old number. They gave me a new number, which turns out to have belonged to a deadbeat woman who went by several different aliases. Collection agencies hounded me until I finally figured it out, and told them that her debts came before 2006, and I had gotten the number in 2007.
This woman had a lot of clients, and once in a while I will get calls from numbers that when I check them right in the white pages, I know that these are people who are looking for her from "days gone by". My real friends and family have real IDs and numbers when they call me. I don't answer the others.
I think Google Voice snapped up some area code 504 numbers, I've gotten texts from 504 numbers to my Google Voice number and GV said if I text back to the number, the from field will be my GV number instead of my cell#. The people the texts were from are not in LA, but TX instead.