Notwithstanding anything contained in Section 26, no deduction or deduction at lower rate at source towards tax payable shall be made under the provisions of the said section from any consideration payable to a dealer or person, if such dealer or person furnishes to the person responsible for paying any amount in respect of the sale or supply or contract referred to in the said section, a certificate in writing, in such form, issued in such manner and by such authority as may be prescribed.