GST appeal limitation strictly confines statutory condonation; exceptional writ review may address defective communication and lost merits hearings.
Section 107 requires a GST appeal within three months from communication of the order and permits condonation only for a further one-month period on sufficient cause. This is a statutory outer limit on the Appellate Authority, which cannot be enlarged through Section 5 of the Limitation Act. Communication through the portal, post or other recognised modes may require factual scrutiny where effective access to the complete order is disputed. Article 226 may exceptionally examine manifest injustice arising from defective communication, prompt action after knowledge, absence of merits adjudication and other credible circumstances, without enlarging the Appellate Authority's statutory jurisdiction.