(a) Under the rules herein prescribed and subject to the limitations hereinafter set forth, the Commission shall have general supervision over the rates charged and service rendered by all public utilities in this State.
(b) Except as provided in this Chapter for bus companies, the Commission is hereby vested with all power necessary to require and compel any public utility to provide and furnish to the citizens of this State reasonable service of the kind it undertakes to furnish and fix and regulate the reasonable rates and charges to be made for such service.