Memberships purchased through the Roblox mobile app via Google Play are recurring by default and will renew at the end of their term using the original payment method. You can cancel at any time before the renewal date. If you cancel a recurring subscription, you will continue to receive membership privileges for the remainder of the already paid time.
Please remember, it is better to cancel sooner rather than later to avoid being charged.
Canceling a subscription via Google Play:
Follow Google's directions to pause, change, or cancel a subscription on Google Play.