How do I cancel a Duolingo subscription and get a refund?

I recently subscribed to a seven day free trial of Duolingo max. Duolingo advertised this as a free trial and I would be reminded that I could cancel my subscription two days before the trial period ended. No reminders were ever sent and I was then charged for a years subscription which I didn’t want. This is fraudulent behaviour and not acceptable.

[Re-Titled by Moderator]