law: The Integrated Goods and Services Tax Act, 2017
  19. Tax wrongfully collected and paid to Central Government or State Government.-
  (1) A registered person who has paid integrated tax on a supply considered by him to be an inter-State supply, but which is subsequently held to be an intra-State supply, shall be granted refund of the amount of integrated tax so paid in such manner and subject to such conditions as may be prescribed.
  (2) A registered person who has paid central tax and State tax or Union territory tax, as the case may be, on a transaction considered by him to be an intra-State supply, but which is subsequently held to be an inter-State supply, shall not be required to pay any interest on the amount of integrated tax payable.