Can we claim Excise duty through Debit Note.

Any one please guide me reg. ED.

For Example : We made Purchase order by mistake for Rs. 100 , but actual price is Rs.80.

The Seller had made Invoice as per P.O. for Rs. 100. adding ED 14.42% and VAT applicable.

At the time of Goods & Invoice received the Buyer found the mistake.

In this case, the Buyer made Debit Note for the price difference of Rs.20. Plus ED & VAT.

Through this Debit Note , whether the Seller can claim the ED what they already paid or not.

Is there any other procedure.

please guide me.