if a bill is entered 2 times in books and on the basis of this gstr3b is filled and tax is paid for sale of 190000 and tax is 17000.no gstr1 is filled.how such bill can be rectified as it relates to feb mth.
If it's related to Feb, 2020 than you can rectify that in current GSTR3B, but on or before 20th October, 2020 Only. Reduce your output tax in current month with wrong invoice. Don't enter that wrong bill in GSTR 1 of Feb.(enter only one invoice, which is right)