iTalki Subscription Charge Dispute After Free Trial Lesson

I entered my credit card information in the iTalki app for a free trial lesson. However, about a week ago, an annual fee of $71 USD was charged to my account without my approval or any clear notification. I did not personally authorize this charge, and no clear or understandable information was provided regarding the billing.

After the payment was processed, I canceled the subscription within the app. Despite this, there has been no information provided about a refund or even a partial reimbursement for the amount charged. Since the payment was made through the card linked to my Google account, I also contacted my bank, but my dispute was not accepted for this reason.

I request that the $71 USD annual fee, which was charged without my consent, be fully refunded to my card as soon as possible.