Taxation Consultant
1823 Points
Joined October 2010
As said by you , the seller has filed gstr 1 for the goods sold by him to the buyer , that means the seller must have issued b2b invoice in the name of the purchaser in gstr 1,
so issue credit note in the name of the buyer using his gstin no .
and if it was a b2c supply , then just reduce the taxable value in the month of april of b2c supply