What does happen if I reach my submissions limit?

What happens if I send out a poll and it gets more submissions than the plan I'm subscribed to? What happens to those submissions?

When the limit is reached the forms will not allow more submissions, they instead will display a message notifying the form's owner has reached the limits. 

I would recommend you to check the following guide in order to get more details about your account usage and limits: https://www.jotform.com/help/408-Understanding-Your-Account-Usage-and-Limits