Any threat, expressed or implied, made to any person engaged in the business of selling motor vehicles at retail in this state by any person engaged, either directly or indirectly, in the manufacture or distribution of motor vehicles, that the person will discontinue or cease to sell, or refuse to enter into a contract to sell, or will terminate a contract to sell motor vehicles, to the person who is so engaged in the business of selling motor vehicles at retail, unless the person finances the purchase or sale of any one (1) or number of motor vehicles only with or through a designated person or class of persons or sells and assigns the conditional sales contracts, chattel mortgages, or leases arising from his or her retail sales of motor vehicles or any one (1) or number thereof only to a designated person or class of persons shall be prima facie evidence of the fact that such person so engaged in the manufacture or distribution of motor vehicles has sold or intends to sell them on the condition or with the agreement or understanding prohibited in § 4-75-408.