Whenever a state bank or a national banking association applies for bank services for itself (hereinafter referred to in this section as "an applying bank") from a bank service corporation which supplies the same type of bank services to one or more other state banks or national banking associations, or both, and the applying bank is competitive with any state bank or national banking association which holds stock in such corporation (referred to in this section as a "stockholding bank"), the corporation must offer to supply such services by either:
(a) Issuing stock to the applying bank and furnishing bank services to it on the same basis as to the stockholding banks, or
(b) Furnishing bank services to the applying bank at rates no higher than necessary to reflect fairly the cost of such services, including the reasonable cost of the capital provided to the corporation by the stockholding banks, at the corporation's option, unless comparable services at competitive overall costs are available to the applying bank from another source, or unless the furnishing of the services sought by the applying bank would be beyond the practical capacity of the bank service corporation. In any action or proceeding to enforce the duty imposed by this section or for damages for the breach thereof, the burden shall be upon the bank service corporation to show the availability of such comparable services or that the furnishing of such services would be beyond the practical capacity of the bank service corporation.