Any person employed by or on behalf of a person residing out of the taxable territories, or having any business connection with such person, or through whom such person is in the receipt of any income, profits or gains upon whom the Income tax Officer has caused a notice to be served of his intention of treating him as the agent of the non resident person shall, for all the purposes of this Act, be deemed to be such agent: Provided that where transactions are carried on in the ordinary course of business through a broker in the taxable territories in such circumstances that the broker does not in respect of such transactions deal directly with or on behalf of a non resident principal but deals with or through a non resident broker who is carrying on such transactions in the ordinary course of his business and not as a principal such first mentioned broker shall not be deemed to be an agent under this section in respect of such transactions: Provided further that no person shall be deemed to be the agent of a non resident person, unless he has had an opportunity of being heard by the Income tax Officer as to his liability.