Refunds for subscriptions and in-app purchases are handled by the platform where you purchased.
Apple (iOS)
If you purchased through the App Store, refunds are managed by Apple.
Request a refund from AppleGoogle (Android)
If you purchased through Google Play, refunds are managed by Google.
Request a refund from GoogleWeb (Stripe)
If you purchased on the web, you can manage your subscription from the Billing page.
If you believe you were charged in error, contact support.