As long as you have an active subscription in place, with a valid payment method, when you use all your credits or the subscription runs out your account will automatically renew with no downtime in service.

If there is no subscription plan in place, the account is at risk of suspension when credits run out. You will receive email notifications to renew your subscription when your current pack has 10% of its original credits remaining. If a new subscription is not in place by the time you run out of credits, the account will be suspended and service will stop.