I e-mailed Ottawa a month after SA, and I wrote "Change of Address for Applicant Being Sponsored - UCI # 924XXXXX - App # F0003XXXXX - My Full Name" in the subject line.
I think it's because I e-mailed them at 3 in the morning, so it was just sitting on top or whatever, would be my best guess. I've noticed that most people note that it takes a couple days at least back to hear from them.
They just sent me an email back in a few hours that said they changed my address.
Did you e-mail Ottawa, or did you accidentally write to Mississauga?