No district shall hereafter pay or agree to pay any agent a fee or other compensation, for services rendered or to be rendered in connection with the acquisition of any property by any such district, which fee or compensation increases with the amount of the purchase price of the property acquired. Every contract in which such district agrees to pay compensation to any agent upon any such basis is hereby declared to be against public policy, illegal, and void; Provided, as to any such contract heretofore made that is legally binding upon any such district, sections 70-619 to 70-624.02 shall not prevent payment of fees or compensation according to the terms thereof. Any officer or director of any such district, who shall authorize, approve, or sanction any such payment or agreement, contrary to the provisions of sections 70-619 to 70-624.02, shall be subject to removal from office therefor in the manner provided by law for removal of county officers and shall be personally liable to the district for the amount paid. The term agent, as used in this section, shall be deemed to include any person, firm, or corporation that seeks to receive payment out of the funds of the district or the proceeds of sale of securities issued by it for acting on its behalf in conducting any transaction relating to the acquisition of property or financing of its indebtedness.