Refunds for subscriptions made via mobile apps are managed by the app store on your device.
You can find the instructions to request a refund on the corresponding store’s help center page:
iOS
Sign in to reportaproblem.apple.com.
Tap or click "I'd like to," then choose "Request a refund."
Choose the reason why you want a refund, then choose Next.
Choose the app, subscription, or other item, then choose Submit.
For more information, see this article on the Apple Support website: https://support.apple.com/en-us/118223.
Android
You can request a refund for your purchase through this link: https://support.google.com/googleplay?p=refundAWF.
For more information, see this article on the Google Support website: https://support.google.com/googleplay/answer/15574897.
Web
To request a refund for a subscription purchased through the web portal, please contact Support. Make sure to include the email address associated with your account.