Duolingo Charged Me $30 Without Subscription or App Store Record

I use the Duolingo app through the App Store. On March $30 was charged to my card through my Duolingo account without my knowledge or approval. Even though I did not manually enter my card details and do not have an active subscription, I only noticed this charge when reviewing my account statement. There is also no record of this transaction as a subscription or purchase within the App Store.

Due to this unauthorized transaction, I have been financially affected and have serious concerns about account security. I am requesting that my Duolingo account be completely closed, that all records related to this transaction be thoroughly investigated, and that the $30 charged to my card be refunded as soon as possible.