Notice asmt-10

for f.y 17-18 ,for a particular month,tax collected in cgst and sgst,and paid under igst.
same reconciled in gstr9c as tax paid under wrong head and shown the difference.
now received notice under asmt-10 demand of tax of less paid cgst &sgst to be paid through drc 03.
what should i reply.?should i pay tax again?