I would think anyone in Canada would know there's been a postal strike as well as those in US states adjoining Canada. What would they suggest retailers do-trudge in muk-luks to their home, deliver in person? Unreasonable.

But then. disappointed customers are often very unreasonable. Perhaps they expected you to use Fed-Ex/UPS/DHL or another Canadian carrier. which you could have done. Using an on-strike service for delivery was your choice~did you send the recipients a note via AMAZON messaging, telling them the order would be late, dependent on when the strike was settled? In your place, if you use Canada Post exclusively, would have put seller account on vacation. USPS is still refusing parcels to Canada until the backlog of parcels are delivered.

Since you've already refunded-and would make that clear in your public response to their feedback-not much can do except apologize and move on.