Gstr 9 error

sir, my client turnover in 17-18 is above 2 crore.i filed Gstr 9 on 30-1-2020 ARN generated.Draft copy shows FINAL.To day when we try to file GST9c,it shows that GSTR9 not File.0n 30january Gstr9 status was filed.but today it shows not file.we try again to file Gstr9,than error shows "Data for transaction I'd already posted".sir,what is problem.we already posted grievance on portal.