Google Play Charged My Account Without Consent and Is Ignoring My Refund Request

Someone took money from my Duolingo account without my knowledge or permission. I asked for a cancellation right away, but after waiting for a reply none has been given. Since I only got a withdrawal warning from my bank—not any notification, password request, or confirmation message for this transaction—this circumstance has left me somewhat worried. My bank told me I had to deal with the matter with Duolingo personally when I contacted them for help. Right now I'm in a frustrating situation where my money has been taken without my permission and I'm not getting the help I need to fix it. I respectfully ask that the money be repaid straight away to my account.