The part against the plaintiff falling under the amount ordered to be paid under the judgment of the first instance shall be revoked.

The defendant.

1. Basic facts

A. The Plaintiff is a company with the business purpose of indoor interior interior interior design and construction business, and the Defendant is a person who sells construction materials, etc.

B. Upon receipt of construction materials from the Defendant, the Plaintiff paid KRW 3,093,750 on June 12, 2017; KRW 9,077,970 on July 4, 2017; KRW 5,000,000 on July 29, 2017; KRW 22,171,720 on October 26, 2017; and the Defendant issued a tax invoice of KRW 12,171,720 on June 30, 2017 to the Defendant; KRW 25,598,20 on July 31, 2017; and each tax invoice was traded between the Plaintiff and the Defendant on September 28, 2017.

[Ground of recognition] Facts without dispute, Gap evidence Nos. 1 through 6, the purport of the whole pleadings

2. The parties' assertion

A. The Plaintiff received construction materials equivalent to KRW 14,857,920 from the Defendant (i.e., KRW 12,171,720, KRW 2598,200) and paid KRW 22,171,720 to the Defendant by mistake. As such, the Defendant is obliged to pay the Plaintiff the difference in unjust enrichment (= KRW 22,171,720 – KRW 14,857,920) and delay damages therefrom.

B. Construction materials equivalent to KRW 7,313,800, including KRW 5,000,000 on July 19, 2017, as the Plaintiff’s on-site manager, decided to guarantee the Defendant’s payment for the portion of “E”, the Plaintiff’s claim cannot be responded to the Plaintiff’s request as it is reasonable for use.

3. Determination

A. In light of the aforementioned facts, the following circumstances acknowledged as follows, namely, the Defendant’s head of the sales office (Evidence A6) against the Plaintiff did not state the details of KRW 5,000,000 that the Plaintiff paid to the Defendant on July 19, 2017, and the Defendant’s payment of KRW 5,00,000 from the Plaintiff on October 26, 2017 was written in KRW 2,313,80,000.