Reversal of input tax credit where supplier fails to file return; recipient must reverse and may reclaim later. Rule 37A requires reversal of input tax credit where a recipient availed credit in FORM GSTR-3B but the supplier did not file the corresponding FORM GSTR-3B by the prescribed cut off; the recipient must reverse that credit while furnishing its own FORM GSTR-3B by the later statutory return date, failure of which makes the amount payable with interest, and the recipient may re avail the credit if the supplier subsequently files the omitted return.