I allow 20 days, from anywhere in North America, based on over 30 years dealing in mail order.
And 30 days from Asia.
After that, a polite note to the seller asking date of shipping, service used and tracking number.
(The tracking number is useless to the buyer, but it makes dishonest sellers nervous.)
If you don't get a satisfactory answer, and an offer of anything but a full refund is unsatisfactory, go to the Resolution Centre at the bottom of this page.
For the record, as of Saturday July 2, Canada Post is in a position to lock out its employees over labour negotiations.
This is NOT your seller's fault in any way.