Every rating organization shall make reasonable provision in its bylaws, rules, constitution, or otherwise to permit any insurer engaged in the kind of insurance for which rate-making is done by such rating organization to become a member or subscriber to its rating services for any kind of insurance, or subdivisions thereof, upon application therefor by such insurer. No rating organization shall discriminate unfairly between insurers in the condition imposed for admission as subscribers or in the services rendered to either members or subscribers. No rating organization shall adopt any rule the effect of which would be to prohibit or regulate the payment of dividends, savings or unabsorbed premium deposits allowed or returned by insurers to their policyholders, members or subscribers. The refusal of any rating organization to admit an insurer as a subscriber shall, at the request of such insurer, be reviewed by the commissioner at a hearing held upon at least 10 days' notice to such rating organization and such insurer. If the commissioner shall find that the insurer has been refused admittance to such rating organization as a subscriber without justification, he shall make an order directing such rating organization to admit such insurer as a subscriber. If he shall find that the action of the rating organization in refusing admittance to an insurer as a subscriber is justified, he shall make an order affirming its action.