Regarding prob in filing of gstr 3b

For GST purposes, CN will be issued by the supplier and not the recipient.

After supplier issues the CN, the recipient will reverse the ITC in GSTR-3B under column 4(B)(2).

No need to do anything in GSTR-1.

From the point of view of supplier:

He will deduct the CN taxable value and tax in GSTR-3B column 3.1(a).

And will mention the CN details against the corresponding invoice in GSTR-1.

The said CN will reflect in the recipients GSTR-2A.