Zero-rated supplies entitlement: IGST refund cannot be denied solely because exporter claimed higher drawback; statutory rules prevail.
The statutory refund regime treats the shipping bill as a deemed application for IGST refund on exports and allows withholding of refund only in the specific, enumerated circumstances provided by the rules. Administrative circulars cannot override the statute; availing a higher duty drawback or technical limitations in departmental systems do not, without falling within the prescribed withholding contingencies, defeat an exporter's entitlement to IGST refund for zero-rated supplies.

Input Tax Credit time limit: GSTR 3B is a temporary stopgap and does not fix the statutory monthly return deadline.
The Court held that GSTR 3B was implemented as a temporary stopgap and was not intended to replace the statutory monthly return; an administrative press release treating GSTR 3B filing as the outer date to avail Input Tax Credit conflicted with the statutory time limit provision and the rules prescribing the monthly return form and manner.