Apple has instructions for canceling subscriptions from non-Apple devices: https://support.apple.com/en-us/HT202039 https://support.apple.com/en-us/HT202039 As

Apple has instructions for canceling subscriptions from non-Apple devices: https://support.apple.com/en-us/HT202039 https://support.apple.com/en-us/HT202039 As a last resort (e.g. if all you have is an Arduino), they advise you to contact Apple support. I'm pretty sure it would be unlawful to have no way to cancel other than with an Apple device.