Export Input Credit Refund Not Allowed by GST Officer

GST Officer Said to Exporter >>> Your Input Supplier Not Yet Filed GSTR - 3B (monthly return)

So I am unable to Allow Your Export Input Credit Refund Claim . 

---- This is a Verbal Direction by GST Officer ==== No Written Direction 

Question :  Exporter's Input Supplier Not Filed GSTR-3B for June'2020 ===

                 Why Exporter's Input Refund Claim is Rejected by GST Officer ???

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