If you need to resend a campaign open the SMS Send campaign screen and click advanced.
Here you will see Resend and Nudge
This resends the entire campaign again. It will reuse the links sent the first time you've sent the campaign. You can however change the words in the message template.
Nudge differs slightly from Resend. Firstly, it's only available for survey/feedback campaigns. With Nudge it will resend the link again used the first time it was sent but not to everyone. It will only send it to the people who have not submitted.
For both nudge and resend any new contact added to the group since the first message will be sent a new message. Any contact that has been deleted or opted-out will not receive a resend/nudge message.
Price of resend/nudge
For both Nudge and Resend you will be presented with an estimated charge. The calculation is done when it's sent. Please note that you will only be charged for the price of the SMS delivery.