Duty drawback (dbk) and terminal excise duty (ted)

Dear All.

One of the my clients has supplied a machinery to UMPP i.e. Ultra Mega Power Project against afavcne authorisation and have claimed TED and DBK for such supply. 

Invoice and other documents were prepared mentioning the name of product as it was mentioned in the list attached with Invaidation Letter which was not exactly matching with the descripttion as mentioned in the DBK Tariff Schedule but functioning of the same is matching with DBK Tariff.

Now Jt. DGFT is asking us to prove that the product is falling under the DBK Tariff which we have mentioned. 

Please suggest me how to proceed further.