Auto-refill is a service we offer to make sure you never run out of data and thus avoid annoying service suspensions. Auto-refill when turned on will automatically add a preselected amount of data when your data balance falls below 100 MB or your days of validity reaches 0. You can turn auto-refill on or off in your Droam account page. You will need to provide a credit card in your account page for auto-refill.