I was a Canadian resident at the time, I just happen to buy the iPhone when I was in Denmark for a brief while. I reckon the iPhone has been turned on 90% in Canada, 5% in Denmark, and 5% in all other countries combined.
The country where the phone was purchased is what matters, not where it has been used.
You would need to make a claim under Danish consumer law (which may have stronger consumer protections than Canadian law?), or check if there are similar battery-gate cases in progress in Denmark and the EU.