Check the status of In-App Subscription in Android

I haven't tested this, but could you use the autoRenewing field in INAPP_PURCHASE_DATA?

If true, the subscription is active, and will automatically renew on the next billing date. If false, indicates that the user has canceled the subscription.

http://developer.android.com/google/play/billing/billing_reference.html#getBuyIntent

Apparently, the autoRenewing field was added or at least documented in the beginning of 2015.

You can check the purchased subscriptions inside the app via

Edit: For subscriptions use "subs", for inapp-purchases use "inapp" e.g.:

Inapp-Purchases: mService.getPurchases(3, getPackageName(), "inapp", null);

Subscriptions: mService.getPurchases(3, getPackageName(), "subs", null);

See also Querying for Purchased Items at http://developer.android.com/google/play/billing/billing_integrate.html

So you can implement a task in your app where you check if the user still has a subscription. If not, you can remove the premium status. Moreover this information could be useful for you:

When the user cancels a subscription, Google Play does not offer a refund for the current billing cycle. Instead, it allows the user to have access to the canceled subscription until the end of the current billing cycle, at which time it terminates the subscription. For example, if a user purchases a monthly subscription and cancels it on the 15th day of the cycle, Google Play will consider the subscription valid until the end of the 30th day (or other day, depending on the month).

source: http://developer.android.com/google/play/billing/billing_subscriptions.html under subscription cancelled

Hope this could help you

Edit2: Because the AIDL library which is mentioned in my answer is deprecated and deactivated in the future, it is recommended to switch to the new Google Play Billing Library.