Cancelling Your Apple iTunes Subscription
Developers are unable to cancel Apple iTunes subscriptions directly. Follow these steps to cancel through your Apple ID:
Read the official Apple article on how to cancel subscriptions.
Ensure you're using the same Apple ID that you used to subscribe.
Go through the steps outlined in the article.
Note: Double-check that you're logged in with the correct Apple ID, and if needed, follow the steps in the article again.
Related articles:
β[iOS] How do I get a refund for iOS app?