Thank you all for your support!
I don't know if it was the support of the employee at the Shoppers' Drug Mart post office (who called the CP depot with my complaint when I picked up the original parcel) or, if I was lucky enough to get a CP employee who actually feels that he needs to do his job.
In any event, this afternoon, I got a call at the door from Canada Post. Told him I'd be right down. Took my cart down, met the mail person, picked up the boxes and took them home.