user_canceled: user canceled subscription manually;
billing_issue: there was an error during billing;
declined_price_increase: user did not agree to a recent price increase;
unavailable_product: product was not available for purchase at the time of renewal;
unknown_error: unknown error occurred.
app_issue: user canceled his subscription due to an actual or perceived issue within your app;
another_reason: subscription was canceled for another reason, for example, if the user made the purchase accidentally.
none: user has never purchased a subscription;
trial: user has a subscription that is currently in trial period;
intro: user has a subscription that is currently in introductory offer;
regular: user has a subscription with regular price;
promo: user has a subscription that is currently in promotional offer;
refunded: user has refunded a subscription;
expired: subscription lapsed.