The right of any person, firm, corporation, receiver or trustee to institute and prosecute in the ordinary courts of justice, any action, suit or motion against any public utility, or public service corporation, or any individual, person, firm, corporation, receiver or trustee, engaged in the public utility business, shall not be extinguished or impaired by reason of any fine or other penalty which the Corporation Commission may impose or be authorized to impose upon such public utility, public service corporation, or any individual, person, firm, corporation, receiver or trustee engaged in the public utility business, because of its breach of any public duty or because of its failure to comply with any order or requirement of the Corporation Commission; but in no such proceeding by any person, firm, corporation, receiver or trustee, against such public utility, public service corporation, or any individual, person, firm, corporation, receiver or trustee engaged in the public utility business, nor in any collateral proceeding, shall the reasonableness, justness, or validity of any rate, charge, service, practice, rule, regulation or requirement, theretofore prescribed by the Corporation Commission, within the scope of its authority, and then in force, be questioned.
