Dear Abhishek, You should rectify previous GSTR-1 wrong entries in succeeding month GSTR-1 return. You should also adjust difference amount of tax payble/receivable in succeeding month GSTR3B return. Regards, Naveen Singh 9716822331
First take month vise filed data from both return prepare reconciliation sheet month vise.. if sales is shown in gstr1 but not in gstr3b- pay in March 3b or vice versa if sales is not shown in both the return - show in both return