Wouldn't just cancelling the card and sending them a email to their support email saying "I hereby give notice I have cancelledy subscription and further attempts to come will fail".
I doubt any court would go against the consumer in that situation. Especially if you never login or use the service again.
I don't know the legal details but court is a far off thing. Companies don't have to accept arbitrary notices and can send your account to collections for being past-due according to whatever terms you accepted for the subscription.
I doubt any court would go against the consumer in that situation. Especially if you never login or use the service again.