Unjust enrichment applies to provisional assessment refunds, and invoice silence triggers the presumption that duty was passed on.

Refunds arising from finalisation of provisional assessment become subject to the doctrine of unjust enrichment where the amended Rule 9B incorporates the bar under Section 11B of the Central Excise Act, 1944, so such refunds cannot escape that restriction. Where duty is not shown separately in invoices, Sections 12A and 12B create a presumption that the duty burden has been passed on to the buyer, and the claimant must rebut that presumption with evidence. On the stated facts, no rebuttal was produced, so the refund was treated as hit by unjust enrichment and the presumption of passing on duty operated against the claimant.

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Issues: (i) Whether the doctrine of unjust enrichment applies to a refund arising on finalisation of provisional assessment under Rule 9B of the Central Excise Rules, 1944 after the amendment; (ii) Whether, in the absence of separate indication of duty in invoices, the statutory presumption of passing on the duty burden applies.

Issue (i): Whether the doctrine of unjust enrichment applies to a refund arising on finalisation of provisional assessment under Rule 9B of the Central Excise Rules, 1944 after the amendment.

Analysis: The refund arose only on finalisation of provisional assessment, and by the time of such finalisation Rule 9B had already been amended. The amendment made the refund under that rule subject to the doctrine embodied in Section 11B(2) and Section 11B(3) of the Central Excise Act, 1944. The legal effect of the amended rule was that refunds arising in such circumstances could not escape the bar of unjust enrichment.

Conclusion: The doctrine of unjust enrichment applied to the refund, and the objection of the assessee failed.

Issue (ii): Whether, in the absence of separate indication of duty in invoices, the statutory presumption of passing on the duty burden applies.

Analysis: The assessee did not show the duty amount separately in the invoices. In such a situation, Sections 12A and 12B of the Central Excise Act, 1944 create a presumption that the duty incidence has been passed on to the buyer, unless the contrary is proved. No material was produced to rebut that presumption.

Conclusion: The presumption of passing on the duty burden applied against the assessee.

Final Conclusion: The refund was hit by unjust enrichment, the lower appellate order was unsustainable, and the original adjudication rejecting the refund was restored.

Ratio Decidendi: A refund arising from finalisation of provisional assessment becomes subject to unjust enrichment once the governing rule is amended to so provide, and the statutory presumption of passing on duty operates unless rebutted by the claimant.

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