In Formaloo there are two ways that we can prevent our users answer a form multiple times.

One way is to limit one entry per IP.

The other way is to show the widget once per time. This works when you embed your forms as a widget to your website and you want to show the widget only once to your users.

To enable it, head to your form, open the settings tab, choose 'Show widget once per user', turn it on, and prevent multiple submissions to your form.