Input tax credit transitional rules require existing law disposal of refund claims and convert unrecovered liabilities into tax arrears. Transitional provisions require disposal under existing law of refund claims, appeals and proceedings relating to input tax credit, tax, interest or other amounts initiated before, on or after the appointed day; amounts found refundable under the existing law must be refunded in cash under that law, rejected portions lapse and any recoverable amounts not recovered under the existing law become arrears of tax under this Act and are not admissible as input tax credit under this Act.