What happens when my Zendesk Support account expires?
Even though your Support account is still accessible for a time after it has expired or been suspended, no tickets or emails will reach your Support account and you won't be able to respond to old ones until we process the payment. The suspension will also temporarily invalidate your SSL certificate until payment is processed.
About 7 days after your account reaches the state where you no longer can receive or reply to tickets, the account becomes completely inaccessible.
For more information about billing issues, see these articles: