Interest on delayed excise duty payment and penalties for rule contraventions, including confiscation and invoice-related sanctions. Failure to pay excise duty by the due date attracts interest from the day after the due date until payment; prolonged default and consignment wise non payment pending Cenvat credit utilization remain liable to interest. Contraventions such as removal, non accountal, manufacture without registration, possession or dealing in liable goods, and issuing invoices without delivery expose the offender to confiscation and prescribed penalties, including penalties measured by ineligible Cenvat benefit or fixed statutory amounts.