Having an app key issued counts as permission in my book. Subscription refunds should be limited to the period during which service was not provided.

And good luck negotiating anything with a billion dollar company, they'll be happy to stiff you if they want to but in the meantime you are beholden to the terms of the contract. This because they typically have legal staff and you probably don't so there is a huge asymmetry in any kind of legal tussle with them.