In case of failure on their part to agree the Commission shall supervise and fix all agreements, contracts, rates or the divisions thereof and rules and regulations between or among common carriers and telephone and telegraph companies, of whatever kind, placed under the control or supervision of the Commission.

Except insofar as rates, transactions affecting rates, or transactions affecting service areas are concerned, the provisions of this section do not apply to transactions between a telephone cooperative association and its subsidiary corporation or cooperative association.