Customs refund procedure: statutory claims require prescribed applications, proof of non-passage of duty burden, and timely processing. Refund of Customs duty and interest is available where duty was paid in excess; claims are governed by Section 27 of the Customs Act, 1962 and require a prescribed application with supporting documents, notification within the statutory limitation (subject to specified exceptions), and a substantive examination to ensure the burden was not passed on. Approved refunds are paid to claimants except where unjust enrichment rules or specified exceptions require transfer to the Consumer Welfare Fund.