Mismatch rectification requires e commerce operators and suppliers to correct reported transaction discrepancies or face added output tax liability. Former Rule 79 required electronic communication of mismatches between e commerce operator and supplier data via FORM GST MIS 3 and FORM GST MIS 4; suppliers and operators could rectify the reported discrepancies in the statement for the month in which the discrepancy was made available, and any unrectified amount would be added to the supplier's output tax liability in the subsequent month's GSTR 3 return with applicable interest, the addition and interest being notified electronically on the common portal.