Article 51 Emergency numbers and operator assistance 1. All service providers referred to in paragraph 2 of this article shall make available: a) Free-of-charge emergency call services enabling the direct dialing of emergency telephone numbers to contact the medical, police, fire brigade and such other emergency services as the Authority may require; b) Operator assistance services, including assistance with call setup, information services on conditions of access to operator services, and fault remedy services; and c) A customer service call centre to receive complaints and provide prompt assistance with subscription, billing and collection. 2. This article shall apply to: a) All service providers operating and providing retail public mobile communications services; and b) All service providers operating and providing retail access to public telephone networks at a fixed location. 3. The Authority may require service providers mentioned in the preceding paragraph to introduce a shared directory, setting the obligations of each service provider in this area, the methods of inclusion and update of the numbers of the service providers’ subscribers in such shared directory, and responsibility of the service providers for the costs of maintaining, updating and providing the shared directory. 4. The Authority may issue regulatory measures to secure implementation of, and compliance with, this article, and the making of such regulatory measures shall be subject to paragraph 4 of article 19. 1. Article 52 Subscriber complaints and disputes A subscriber whose complaint or dispute has not been treated by a service provider in accordance with subparagraph b) of paragraph 1 of article 50 may apply to the Authority for an order requiring the service provider to either: a) Reconsider and properly address the complaint or dispute in accordance with subparagraph b) of paragraph 1 of article 50; or b) Provide a specific remedy for the complaint or dispute. 2. The Authority may require service providers to: