Wrongful tax classification: refund available where intra state treated as inter state, and no interest on state tax. A registered taxpayer who pays central tax and State tax on a supply treated as intra State but later found to be inter State is entitled to a refund in the prescribed manner and subject to conditions; where integrated tax was paid believing a supply to be inter State but it is later held to be intra State, no interest is required to be paid on the State tax payable.