Deemed export refund evidence: suppliers must submit acknowledgements and undertakings under CGST rules to claim refund. Suppliers claiming refund for deemed export supplies must produce either an acknowledgment by the jurisdictional tax officer of the Advance Authorisation/Export Promotion Capital Goods Authorisation holder or a tax invoice signed by the recipient Export Oriented Unit confirming receipt, together with undertakings from the recipient that no input tax credit has been availed and that the recipient will not claim refund so the supplier may do so.