Section 924 - Prohibitions and changes in preferred carrier selection(a) No carrier shall bill for intrastate telecommunications services, nor solicit to provide intrastate telecommunication services, within the State, unless such carrier has received a certificate of public convenience and necessity from the Commission.(b) No submitting carrier shall submit a change in the customer's selection of a carrier prior to obtaining:(1) Authorization from the customer; and(2) Verification of that authorization in accordance with the procedures prescribed in this subchapter and implementing regulations of the Commission.(c) No carrier shall bill or collect from any person a charge for any product or service to which such person has not agreed or subscribed, nor for any amount in excess of that specified in the tariff, price list or contract governing the charges for such services. 72 Del. Laws, c. 487, § 1.;