You can set a low balance notification threshold from your @voice account. The notification will automatically send you an email (email as per your profile) whenever your balance has arrives at a specific threshold. To set this up, go to 'Profile' -> 'Low Balance Notification'.
The default value for the Low Balance Notification is set at:-
- 1st Threshold - 50% of your credit limit
- 2nd Threshold - 75% of your credit limit
- 3rd Threshold - 85% of your credit limit