department forcing us to pay tax instead of forcing the supplier.

we have claimed itc in our gstr3b in basis of the supplier's invoice and payment made to supplier for the purchase against the concerned invoice but the supplier has not yet filed his return therefore the department is seeking to raise notice against us for demand of unmatched ITC . instead of forcing us to make payment shouldn't the department force the supplier for the payment and filling of return.? we have already paid to the supplier . why do we pay double tax for a single purchase while the tax has already been paid to the supplier..? now we found that the suppliers registration has been cancelled. now what will be happen to the entire credit claimed by us .?