A. On March 2, 2014, the Plaintiff entered into a subcontract for construction works for soil and incidental civil engineering works (hereinafter “instant construction works”) among “the construction works for the Personnel Center by the Korea Railroad Technology Institute,” which is an end-user institution (hereinafter “the instant construction works”), with the Korea Railroad Technology Institute Co., Ltd. (hereinafter “Seoul”) and the Korea Railroad Technology Institute entered into a contract for the modification of the construction amount of KRW 916,30,000 from March 2, 2014 to August 14, 2015. < Amended by Act No. 12542, Aug. 15, 2014>

B. On April 30, 2014, Gyeongnam Company entered into a contract on the payment guarantee of subcontract consideration with Defendant Construction Mutual Aid Association for the period from April 12, 2015 to November 12, 2015, with respect to the obligation to pay subcontract consideration to the Plaintiff of the instant construction project to the Plaintiff of Gyeongnam Company.

C. From May 20, 2014 to March 3, 2015, the Defendant Korea Railroad Technology Institute paid 8,377,083,000 won for the total amount of construction cost on the basis of the payment of construction cost on six occasions to Gyeongnam enterprises. Of them, the payment of construction cost for the portion of the civil engineering works was made on April 20, 2014; KRW 290,400,000 on June 30, 2014; KRW 607,00 on November 11, 2014; KRW 151,80,000 on December 29, 2014, respectively.

As of April 30, 2015, the Plaintiff received 697,088,967 won (the amount after deduction of employment insurance premiums) from 701,470,000 won for construction costs of the instant construction project, excluding additional construction works, from the Gyeongnam Enterprise. The aforementioned amount includes the following: (a) the issuance date of the Gyeongnam Enterprise; (b) the face value of 61,214,720 won; and (c) the maturity of 30 April 30, 2015; (b) the issuance date of electronic bills; (c) the maturity of 52,251,136 won; and (d) the maturity of 52,251,136 won; and (c) the issuance date of electronic bills, the face value of 32,253,383 won; and (d) the electronic bills, the maturity of which is May 30, 2015;

On April 7, 2015, the Plaintiff started rehabilitation procedures for the Gannam Company, and was not entitled to receive each of the aforesaid electronic bills (hereinafter “each of the instant electronic bills”).