(1) Certificate holders shall report promptly in writing to the commission, and to the public along the route, all interruptions of regular service, where such interruptions are likely to continue for more than twenty-four hours. Said report to include a full statement of the cause of such interruption and its probable duration.

(2) Discontinuance or suspension of service by a certificate holder for a period of five consecutive days without notice to the commission shall be deemed a forfeiture of all right secured under and by virtue of any order or permission to operate, issued by the commission: Provided, however, That the commission may permit the resumption of operation after such five-day discontinuance or suspension, on proper showing that the certificate holder was not responsible for the failure to give service or notice.