A. On January 12, 201, the Plaintiff entered into a contract for mobile communications service (hereinafter “instant contract”) with the Defendant, who is a telecommunications business operator, to enter into a mobile network service contract with the Defendant for the phone number B, and subscribed to 55 “the said fee system” (hereinafter “instant fee system”).

The contents of the Defendant’s terms and conditions of use (hereinafter “instant terms and conditions”) consenting to the Plaintiff at the time of entering into the instant contract are as follows.

Part III. (Duties of Parties to the Contract) ① Company shall notify the customer of the major contents of the contract and the use of services, such as the charge system, additional services, customer complaint settlement body and telephone number, object of reduction of or exemption from charges, criteria for suspension of use and ex officio termination at the time of entering into a mobile telephone service contract, and if the customer fails to notify, it may not claim his/her rights.

(15) Where important matters (charges, additional services, etc.) related to the services provided by a company at the option of a customer are modified, the company shall notify the customer through Sms, E-mail, etc. and post a notice on the details of the change on its website.

B. On January 13, 201, on the day following the date of the conclusion of the instant contract, the Plaintiff filed an application for the attached services of TNpphering OPD (T Data Person Device) provided by the Defendant (i.e., service sharing data capacity at a fare system so that the USIM card can be registered by up to five registrations for each line of mobile communications services; hereinafter “instant additional services”) with the USIM card granted by the Defendant. On the same day, the Plaintiff obtained and used the USIM card on one day.

C. The defendant, at the time of withdrawal of data unlimited rate system, shall provide the supplementary service in this case.