GSTR 4 purchase Clarify

Sir I have a slight suspicion

Gst No Feb 20 Reg (Regular)

The time he took did not open the Lock Down store

He has changed composition since 01/04/20

May 20 Opens the shop

Feb20 Mar 20 GSTR 3B Nil Return Filed (Ordered By Phone In March For Rs 7 Lakhs)
It has come to 2A
3B ITC did not claim as he did not receive the goods bill for the shop

Now GSTR 4 20-21 should be put.