If you receive a notification from CallFire that your account balance has fallen below zero (0) credits, your calls and texts will stop.
CallFire will never disconnect a call in progress. If a call is active at the time your account runs out of credits, you may incur a negative balance. These charges will be added to your next purchase.
You can protect against this happening by setting up an auto-pay to fund your account if the balance falls below a predefined threshold. You will find that setting in the Low Balance Settings of your Account Information page.