Transitional GST provisions preserve refund and credit rules while shifting recovery and taxability to the new regime. Transitional GST provisions set out that returns of goods sold within six months before the appointed day may attract refunds of tax paid under existing law when returned by unregistered buyers, while returns by registered persons are deemed supplies; price revisions under pre appointed contracts require supplementary invoices or debit notes for upward revisions and permit credit notes for downward revisions subject to recipient reduction of input tax credit; claims, appeals and proceedings under the existing law must be disposed under that law, with refundable amounts paid in cash and recoverable amounts treated as arrears under this Act and excluded from input tax credit.