A. On September 14, 2012, the Defendant entered into a contract for delivery of recyclable scrap metal with B Co., Ltd. (hereinafter “Nonindicted Company”) and the main contents are as follows.

The defendant supplies the scrap metal arising from the defendant's place of business to the non-party company.

The non-party company shall pay a certain amount as an advance payment to the defendant within the extent not exceeding the amount of the scrap metal for one year, and the non-party company shall be subtracted from the said advance payment to the extent that the non-party company collects the scrap metal.

B. Around that time, Nonparty Company paid KRW 200,000,000 to the Defendant as advance payment.

C. The Plaintiff was one of the co-representative directors of the non-party company, and on December 2012, the Plaintiff succeeded to the contractual status of the non-party company with the consent of the non-party company and the defendant.

Since then, the Plaintiff continued to engage in scrap metal transactions with the Defendant under his/her own personal business chain “C” and paid KRW 250,000,000 as advance payment from October 4, 2013 to December 2, 2013, separate from the above KRW 200,000.

The defendant refused to supply scrap metal around March 2015 and suspended transactions with the plaintiff. At the time of the suspension of transactions, the balance between the non-party company and the plaintiff after deducting the scrap metal from the advance payment made by the plaintiff is KRW 154,679,952.

[Ground of recognition] Unsatisfy, entry of Gap evidence 1 to 8, purport of whole pleadings

2. Determination

A. According to the fact that the obligation to return advance payment occurred, the transaction between the original Defendant and the original Defendant is deemed to have terminated by the Defendant’s refusal to supply the said advance payment. Therefore, the Defendant is obligated to return KRW 154,679,952, which is the balance of the advance payment already received to the Plaintiff.

B. As to the Defendant’s allegation of set-off and counterclaim claim, the Plaintiff, while collecting scrap metal from the Defendant, unjustly gains KRW 240,39,927 by applying a much lower unit price than the market price or by deceiving weight.

Accordingly, the defendant set off the plaintiff's claim for return of unjust enrichment with the plaintiff's claim for return of advance payment.