refund within fifteen days from the date the dealer furnishes the security to his satisfaction under sub- section (5). (7) For calculating the period prescribed in clause (a) of sub- section (3), the time taken to – (a) furnish the security under sub-section (5) to the satisfaction of the Commissioner; or (b) furnish the additional information sought under section 59; or (c) furnish returns under section 26 and section 27; or (d) furnish the declaration or certificate forms as required under Central Sales Tax Act, 1956, shall be excluded (8) Notwithstanding anything contained in this section, where – (a) a registered dealer has sold goods to an unregistered person; and (b) the price charged for the goods includes an amount of tax payable under this Act; 5(c) the dealer is seeking the refund of this amount or to apply this amount under clause (b) of sub-section (3) of this section; no amount shall be refunded to the dealer or may be applied by the dealer under clause (b) of sub-section