If you've run out of credits half way through a Campaign, not to worry!
You'll first need to top-up your credits via the Buy Credit link, in Admin > SMS & Email.
Once you've topped up, you can head on over to Marketing > Campaign Report.
Specify your date range for when the Campaign was sent, and locate the Campaign that you're looking to re-send.
Once you've clicked Re-Send, you need to choose if you want to to re-send the campaign to everyone, or to failed recipients only.
If you want to re-send it to everyone on this campaign list, click All Recipients.
If you want to re-send it to client's with messages that failed/had an error, click Failed Recipients Only.