We are pvt ltd co. One of our customer returned us some good in May 2012 purchased by him in March 2012. But for this we have not raised credit note against him. Now in December 2012 that customer want to raise credit note agaisnt him for same transaction. How shoudl i give effect of VAT in credit note. Will sales tax department allow if credit note if given after 6 months whihc includes VAT?