credit note

we generate a tax bill to clients in the month of November 18 and according we paid GST to Govt. Now party rejected the invoice. in the month of December we generate Credit note. in December month we have no sales. therefore we have exceeded Tax amount which we paid to govt earlier. Now question is how we show credit notes figure in Gstr 3b and which column. so that we can see the excess tax paid by us to show our electronic credit ledger