IGST refund transmission delays: interim sanction on undertakings and CA certificates pending GSTN records for exporters Sanction of IGST refunds where GSTN has not transmitted records is permitted through an interim procedure: Customs will identify exporters with reconciled cumulative IGST between GSTR 3B and GSTR 1 for transmission by GSTN, require submission of Chartered Accountant certificates confirming no discrepancy, and for short payments mandate payment of shortfalls with proof and undertakings; processed refunds remain subject to post refund audit and verification by jurisdictional GST officers.