Negative figure for sales

Same case is with me,

For Example: I have made sale to Gujarat of Rs.500/- in May 2018, but there was sales return in June 2018, and have made sale to M.P of Rs.1000/-, In this case while filing GSTR3B I will less the amount of Rs.500/- from Rs.1000/- and show taxable sale of Rs.500/- and will pay IGST accordingly. But case is, sale has been made to unregistered dealer so I have to also mention in 3.2 column in GSTR3B also. My question is that I will be inserting sale of MP Rs.1000/- but how to show (-500) figure in GSTR3B in 3.2 column beside to 3.1 column to match both column, as it is compulsory to match both colum.

Kindly reply soon need to file GSTR3B

Same here. Still trying to figure out the work around. Disappointed that GSTN still doesn't allow negative value in state wise sales under GSTR 3b 3.2 table.