Duolingo Charged Me ₺840 Without Sending the Promised Warning Before Trial Ended

I downloaded the Duolingo app and signed up for a free two-week trial. I thought I would get a message two days before the trial finished. But Duolingo took ₺840 out of my account without my permission, and I didn't get any news. That nasty surprise charge has given me a lot of trouble, and I'm writing this to try to get my money back as soon as possible. Having money taken from me without any notice or permission is very upsetting, and I'm not sure why this happened. I've tried to get in touch, but so far no one has been able to help me. I hope that this problem can be fixed quickly so that I can get my money back.