All payment and billing issues are transparent for you.
It's usually a best practice to set 'Grace Periods' after a renewal payement fails to process.
This is defined by your internal Subscription management policies and set-up directly by your team in each of the Stores.
It's good to know Apple and Android handle Grace Period differently :
Android (Google Play / Huawei) will send us a succession of 24h renewal events until the end of the Grace Period
Apple only sends one renewal event covering rights until the end of the Grace Period
If the payment was still not able to process by the end of the Grace Period then we will trigger a SUBSCRIPTION_EXPIRED event
If the payment information was updated and successfully processed we will trigger a SUBSCRIPTION_RENEWED
We are currently working on refactoring our Events / Properties to give you more insights and nuance on the exact stage of the User / Subscriber lifecycle, which will allow you to implement logic and trigger emails and notifications for the User to act on (update payment cards, targeted promotion to re-engage or convert after trial with a discounted offer)