Null and void contract

Any promise, express or implied, to pay any person any sum of money paid by him under or in respect of any contract or agreement rendered null and void by section 17 of this Act, or to pay any sum of money by way of commission, fee, reward or otherwise in respect of any such contract or of any services in relation thereto or in connection therewith, shall be null and void, and no action shall be brought or maintained to recover any such sum of money.