Tax wrongly collected: refund available when supply reclassified between intra State and inter State, with no interest due on State tax. Where a registered person pays central and State tax on a transaction treated as an intra State supply but later held to be inter State, the taxes so paid are refundable in accordance with prescribed manner and conditions. If integrated tax was paid on a transaction treated as inter State but later held to be intra State, no interest is payable on the State tax determined to be due.