Gstr1 Vs gstr3b

sir I have entered b2b invoices I fy 1819 gstr1 for march 2019 month and amended b2c in gstr1 march 2020 fy 1920 sir.

I have received a notice that there is differences in gstr1 vs gstr3b in fy 1819 sir..

I thought the explain the 2 year gstr1 and gstr3b amendments to gst officials.. will that be valid sir?
pls help me sir I need to explain them by tommorow