(2) Where any export of goods has been made to which a notification under sub section (1) applies, no person entitled to sell or procure the sale of the said goods shall, .except with the permission of the Reserve Bank, do or refrain from doing any act with intent to secure that (a) the sale of the goods is delayed to an extent which is unreasonable having regard to the ordinary course of trade, or (b) payment for the goods is made otherwise than in the prescribed manner or does not represent the full amount payable by the foreign buyer in respect of the goods, subject to such deductions, if any, as may be allowed by the Reserve Bank, or is delayed to such extent as aforesaid: Provided that no proceedings in respect of any contravention of this sub section shall be instituted unless the prescribed period has expired and payment for the goods representing the full amount as aforesaid has not been made in the prescribed manner.