My friend mailed his passport to LA 1.5 months ago, he finally fed up with the wait and went to LA office yesterday in person. He was being told that the immigration visa has been approved and issued a while back, but LA office is extremely busy, so they put all the passport aside, then slowly start mailing it out when they have time.
Furthermore, he was being told that whenever you email LA, you should mention the file number that starts with B, and they normally dont check that email address frequent enough. he was being told the "case specific inquiry" is relatively faster way compare to the LA general email address. Hope the info helps
Link to "case specific inquiry" http://www.cic.gc.ca/english/information/offices/missions/los-angeles.asp