Canada Post Telephone Number - Customer Service - Help - Tracking
Here is a list of numbers to call for any type of help or customer support for Canada Post. I noticed that their link off of Google just brings you to their lame e-mail contact form. So, here they all are, all on one page:
Canada Post General Information: 1-866-607-6301 (Available Monday-Friday 8AM<->6PM local time)
General Canada Post Information Outside of Canada: 1-416-979-8822
If you have a complaint/problem with Canada Post that you have not been able to solve through their regular customer service, consider contacting their ombudsman office at 1-800-267-1177. Only use this if you have been unable to solve your problem/issue through the usual channels.