If your server has been suspended due to an invoice not being paid by the overdue date, services will be restored automatically within a few minutes of payment for all outstanding(payable) invoices being received.
If your server has not come back online after 15 minutes, refresh the invoices page in mPanel and check if there is an additional unpaid invoice preventing your server being unsuspended.
If there are no additional unpaid invoices, and more than 20 minutes have passed since all invoices were paid, please contact support and let us know.