Hey, if u sent yours in Buffalo, here is the information you need:
http://www.canadainternational.gc.ca/buffalo/visas/submit_soumettre.aspx?view=d
At the very end of the page:
"Important information regarding the return of your passports:
Passports will be returned to you by US Postal Service regular mail unless you use one of the premium services described above. WE WILL NOT USE FedEx, UPS, PUROLATOR OR ANY OTHER COURIER COMPANY ENVELOPES - EVEN IF THEY ARE PREPAID BY CREDIT CARD OR ACCOUNT NUMBER."