Debit note credit note

it is purchase return so issue Debit note and get credit note from supplier for the same. and let it show in respective months returns.

Explanation. 1

first of all as per 100%of purchase value of goods should be booked in books of account then you can issue a debit note 3000 nos with original tax invoice no for whatever u knew rejected goods in sept and the same 4000nos in Oct.

Explanation 2 .

if you want to get rejected materials from the supplier then you don't want to issue a debit note its extra headaches for filling of returns just make internal conservation with the supplier and get materials without debit note.if no any problem.