What happens when I suspend a subaccount?
If you suspend a subaccount, Twilio will not remove the phone numbers attached to it and the parent account will continue to be charged for the numbers monthly. We leave it up to the owner of the master account to determine if they want to release the phone numbers of the suspended account, or if they want to implement a grace period.
If you close a subaccount, Twilio will release all phone numbers assigned to it and shut it down completely. Note that closing accounts is an irreversible process.