Fraudulent input tax credit-recipients face demand and penalty; issuers and intermediaries attract penal sanctions. Issuance of tax invoices without underlying supply does not constitute supply under section 7 and does not attract tax demand under sections 73 or 74, but issuers are liable to penalty under section 122(1)(ii). Recipients who fraudulently avail and utilize ITC on such invoices are liable to demand, recovery and penalty under section 74 with interest, and the bar in section 75(13) prevents duplicate penalties. Intermediaries who pass on ITC or issue invoices without supply are not subject to tax demand for non-existent outward supplies but are liable to penal provisions under section 122(1)(ii) and section 122(1)(vii); forfeiture provisions may also be invoked where applicable.