Facebook messaging, make only friends be able too?

[abraXus]

if the other account has already messaged your current account, there is no way to prevent that without blocking that person

in other words, your settings work just fine, you are just not testing them properly

check the options here

http://abrax.us/Facebook/ContactPrivacy.php

and also keep in mind that testing things using multiple accounts that you create yourself will give you mixed results, since it's against the rules to create more than one account, and facebook can tell when you do it