I actually ended up going to UPS instead. They were far more helpful than FedEx. The guy at my local store was very nice and made sure I could send an envelope back to myself. He called UPS customer service TWICE to make sure all my stuff was okay.
The gentleman at UPS helped. He just got my info for the outgoing address and put it on one envelope and the info for the incoming (back to me) address and put that on another envelope and put all my documents (including the self addressed envelope) in the first outgoing envelope.
I paid for both of them.
I used the phone number
613 944 4000 on all my documents. That's for the IRCC office, but not a direct department of any kind I believe. I looked it up on countless government websites so I believe it should be right.
It was a pretty penny to send out ($115 American dollars to send for both envelopes) but it was over night shipping seemed squared away.
IRCC got it the very next day.
I'm still waiting on my paperwork because I had to resend my visa pictures again because I sent the wrong size in the first time, (and this time I simply sent my pictures out through USPS. Bad idea - slow service) but, so far everything seems....okay. I'll let you all know how it goes if I receive any further contact from IRCC! Crossing my fingers still. I'm pushing the time line here!