Take a look at the timelines in the threads for Aug, Sept, and Oct, or on trackitt. The time between when the application arrived at CPC-M and the time for the sponsor approval letter to arrive in the post can take 3-4 weeks and has probably slowed down now because of the Christmas season.
I don't think everyone should call Mississauga just because they are curious about the status of their sponsorship application... if EVERYONE did this you could imagine they would need 2 or 3 staff full-time on the phone just for that... and I would understand if they got cranky unless there is a real, legitimate reason to call. The criteria to be a sponsor are very straightforward and clearly defined. If you meet them you likely don't need to worry, you just need to be patient. We're like you and checking ecas and the mailbox obsessively but still not going to call them until we exceed the timelines of others who've gone through our VO plus a couple weeks to consider xmas hols.
Good luck to you (and to all of us), let's hope we can all find something to distract us so the time goes more quickly.
Cheers,
TLH