(1) Any person who sells or offers to sell a motor fuel franchise in violation of this chapter shall be liable to the motor fuel retailer or motor fuel refiner-supplier who may sue at law or in equity for damages caused thereby for rescission or other relief as the court may deem appropriate. In the case of a violation of RCW 19.120.070 rescission is not available to the plaintiff if the defendant proves that the plaintiff knew the facts concerning the untruth or omission or that the defendant exercised reasonable care and did not know or if he or she had exercised reasonable care would not have known of the untruth or omission.

(2) The suit authorized under subsection (1) of this section may be brought to recover the actual damages sustained by the plaintiff: PROVIDED, That the prevailing party may in the discretion of the court recover the costs of said action including a reasonable attorneys' fee.

(3) Any person who becomes liable to make payments under this section may recover contributions as in cases of contracts from any persons who, if sued separately, would have been liable to make the same payment.

(4) A final judgment, order, or decree heretofore or hereafter rendered against a person in any civil, criminal, or administrative proceedings under the United States anti-trust laws, under the federal trade commission act, or this chapter shall be regarded as evidence against such persons in any action brought by any party against such person under subsection (1) of this section as to all matters which said judgment or decree would be an estoppel between the parties thereto.