After a broadcast has been sent you can track the status of each broadcast method from the broadcast view screen. There are 5 possible indicators that will be shown to you depending on the status of the broadcast to the each recipient at any given time.
Not Sent - The broadcast method has not been selected or it has been selected but there is no available sms/email in the user/contact profile
Sent - The broadcast has been sent out and delivery has been confirmed.
Pending - The broadcast is being processed and is awaiting feedback to confirm delivery status.
Failed - The broadcast has failed and not been delivered. An accompanying message will be shown to explain the reason for failure.
Unknown - The status of the message is unknown.