shall, before conveying any such goods give such security as the Commissioner may require for the due observance of this Act: Provided that the Commissioner may call for special or additional security in respect of any particular transaction or conveyance of goods from any agent or carrier. (4) Any agent (including a representative or associate of the principal) representing or acting for or on behalf of any exporter, manufacturer, supplier, shipper or other principal outside Swaziland who exports goods to Swaziland shall be liable in respect of any goods ordered through him or obtained by any importer by means of his services for the fulfilment of all obligations imposed upon such exporter, manufacturer, supplier, shipper or other principal by this Act, and to any penalties or forfeiture which may be incurred by any such exporter, manufacturer, supplier, shipper, or other principal under this Act: Provided that any such agent shall cease to be so liable if he proves to the satisfaction of the Commissioner that — (a) he was not a party to the non-fulfilment by any such exporter, manufacturer, supplier, shipper or other principal of any such obligation; (b) when he became aware of such non-fulfilment he forthwith notified the controller thereof; and (c) all reasonable steps were taken by him to prevent such non-fulfilment. (5) Every agent of a class referred to in subsection (4) and specified in any regulation for the purposes of this subsection shall register himself with the Commissioner and furnish such security as the Commissioner may require for the due observance of this Act: Provided that the Commissioner may accept such security from any association of such agents, approved by him, which undertakes to give security on behalf of its members. (6) No agent referred to in subsection (5) shall transact business on behalf of any exporter, manufacturer, supplier, shipper or any other principal after a date specified by the Minister by notice in the Gazette unless he has complied with subsection (5). (7) The registration and operation of any agent referred to in subsection (5) shall be subject to such conditions as the Commissioner may impose by rule and the Commissioner may cancel the registration of an agent who has persistently contravened or failed to comply with this Act or has committed an offence referred to in section 80, 83, 84, 85 or 86. Agent may be called upon to produce written authority. 100. If any person makes an application to an officer to transact any business on behalf of another person or if any person represents himself to an officer as the agent of another person, such officer may require the person so applying or representing himself to produce a written authority in‟ a form approved by the Commissioner from the person on whose behalf the application is made or on whose behalf the person so representing himself is alleged to