A. The Plaintiff is a company engaged in software development, consulting and supply business, software development service business, etc., and the Defendant Company is a company engaged in information and communications consulting business, etc., and the Defendant C is the representative of the Defendant Company.

B. 1) From around 2013 to August 24, 2018, the Plaintiff and the Defendant Company: (a) provided the Defendant Company’s customer company with document security-related software that the Plaintiff developed according to the Defendant Company’s order to supply, maintain, and repair such software; and (b) provided the Defendant Company with the payment of the Plaintiff at the customer company’s price included in its margin; and (c) in the case of maintenance and repair services, the Plaintiff received the service payment from the Defendant Company in installments; (d) However, from August 4, 2017 to August 24, 2018, the Defendant Company began to pay the Plaintiff for 14 items of supply or maintenance services ordered to the Plaintiff (E, F, G, I, J, K, M, N,O, P).

3) On December 6, 2018, upon receiving a demand notice from the Plaintiff for the payment of the unpaid amount, Defendant C jointly and severally guaranteed the payment obligation owed by the Defendant Company to the Plaintiff to the Plaintiff, and agreed to pay 15% interest per annum from January 1, 2019 if the said obligation is not repaid by December 31, 2018. (4) The said unpaid amount obligation against the Plaintiff by the Defendant Company to the Plaintiff remains 65,965,570 won (hereinafter “instant payment”).

[Ground of recognition] Facts without dispute, entry of Gap evidence 1 through 6 (including branch numbers, hereinafter the same shall apply) and the purport of whole pleadings

2. According to the above facts, according to the judgment on the claim of the principal lawsuit, the Defendants jointly and severally filed a claim amounting to KRW 65,965,570, and the Defendant Company’s claim against the Plaintiff from January 1, 2019.