Regarding vat setoff.

The VAT department will handover the notice to you as well as the defunct company. VAT will be payable by the Director of the company as he has signed the Indemnity Bond during the dissolution of the company that there are no Dues payable by the company to the government, that may be in any form like Income tax, VAT, Service tax, Excise, Customs, etc.

So, you will have to submit your Purchase Invoice, Bank Statement showing Payment is done to the now defunct company to your concerned VAT Officer.

And, I think the credit will be only allowed to you when the concerned director of the defunct company will file his VAT return.Until then you will be disallowed the Input Credit, and if your claim seems viable to your VAT Officer, he will refund you the amount along with Interest.