As a fellow Canadian, I feel your pain.
Out of desperation, I have started using Canada post and USPS.
Guess what?
I'm finding it cheaper, more reliable but, not quite as fast as when the Courier companies get it right.
However, I am getting used to the longer delivery times , usually a couple of days in the difference.
I actually had Cas at Dr. Diff send me a Suregrip differential and a set of 3:55 gears via USPS.
Got it in 8 days!! And I'm in Newfoundland so much longer ways to go.