Transitional input tax credit rules require refund or carryforward treatment and recovery as arrears for pre-existing law liabilities. Transitional provisions require that refunds, credit adjustments and disputes arising under the prior law be disposed of under that law with refundable amounts paid in cash and rejected or reversed amounts not admissible as input tax credit under the GST law; supplementary invoices and credit notes for pre-appointed contracts are treated as outward supplies under the Act, and unrecovered amounts under prior-law proceedings may be recovered as arrears under the GST law but remain inadmissible as input tax credit.