4.2 It is also well-settled that an application under Section 9 of the Code, inter alia , requires strict proof of debt and default. The Applicant must prove with credible evidence and materials that there is an ‘operational debt’ owed to it by the Corporate Debtor and that there has been a default in payment of such debt on the date on which it fell due and payable. Coming to the facts of the present case, it is observed that while the Operational Creditor claims the amount of operational debt in default to be Rs.12,75,191/- (rounded off) including interest as per the Application, the Corporate Debtor provides a reconciliation statement and claims that all payments due to the Operational Creditor towards principal debt have been remitted and there is no amount due and payable to the Operational Creditor any more. It is noticed from the record that a total of 97 invoices were raised by the Operational Creditor against purchase orders issued by the Corporate Debtor aggregating to Rs.74,80,757/- out of which payments of Rs.66,24,262/- were made by the Corporate Debtor from time to time, leaving an outstanding principal amount of Rs.8,56,495/- and overdue interest charges of Rs.10,25,954/- (rounded off) prior to the issuance of the Demand Notice on 07.05.2019. Subsequently, the Operational Creditor issued the Demand Notice to the Corporate Debtor demanding payment of outstanding dues of Rs.18,82,449/- (Rs.8,56,495+Rs.10,25,954).