In-App annual subscription in error to Babbel - how to get refund?

Dear All,

My wife downloaded a language learning app we think around a year ago. She seems to have subscribed inadvertently, probably through an in-app purchase, and found she had recently been automatically debited around £50 (the can amount can be verified when needed) for another year's subscription.

She's now managed to cancel the subscription in the app setting but was unsuccessful in getting a refund. Babbel suggested Apple should be contacted and I believe Apple sent her back to Babbel.

I'd be grateful for any suggestions how we might appeal to Apple for help with a refund. She used the app in the first year only once apparently but it's unlikely that can be refunded. The issue is the rolling nature of a fairly hefty annual subscription with seemingly no notification, just an automatic bank debit.

Thanks for taking the time to read this.

K