of the whole of Article 83, Section (3) of the Telecommunications Business Act. However, in this case, the investigative agency et al. asked the telecommunications business operators to provide Complainants’ communications data for an investigation, and subsequently, the operators provided the investigative agency et al. with the communications data which contained Complainants’ personal information at their request (the investigative agency et al.’s acquiring communications data through their “request for provision of communications data” and telecommunications service providers’ “provision of communications data” is hereinafter referred to as “the act of acquisition of communications data”). Thus, the subject matter of review is limited to the part of Article 83, Section (3) of the Telecommunications Business Act relating to “a request for communications data from a prosecutor, the head of an investigative agency (including the head of a military investigative agency), or the head of an intelligence and investigation agency.” Complainants also argue that the legislative inaction that the Telecommunications Business Act did not establish ex-post notification procedures violates the Constitution, but this is a challenge to the failure of Article 83, Section (3) of the Telecommunication Business Act to establish ex-post notification to users––in other words, a challenge to insufficient and incomplete legislation. As such, since Complainants ultimately dispute the constitutionality of Article 83, Section (3) of the Telecommunications Business Act, the legislative inaction thereof is not included in the subject matter of review. 3. Meanwhile, Complainant K.M. argues that if Article 83, Section (3) of the Telecommunications Business Act is unconstitutional, then the proviso of Article 83, Section (4) of the Telecommunications Business Act is also unconstitutional, and the above provision should be declared unconstitutional by expanding the scope of a decision of unconstitutionality pursuant to Article 45 of the Constitutional Court Act. Since this is not an independent argument against the constitutionality of the proviso of Article 83, Section (4) of the Telecommunications Business Act, - 25 -