A. On November 15, 2017, the Plaintiff (the Plaintiff and the Defendant entered into a contract with the Defendant (Seoul) to sell the instant medical device with text messages, telephone calls, etc. at KRW 8 million (the contract amounting to KRW 500,000) on the Internet community (the instant medical device) after inserting an article on the sales of the medical device listed in the attached list (the instant medical device).

B. On November 16, 2017, the Defendant remitted the down payment of KRW 500,000 to the Plaintiff.

On November 20, 2017, the Plaintiff delivered the instant medical device to the Defendant via C.

However, in the process of the inspection conducted by the Defendant upon delivery, the problem was found that the tamp in this case’s medical device malfunctions off (at least 1cm below the marked image), the problem was that part of the edge of the tamper (the Plaintiff used the medical device in this case in the state where the tamper was not installed, but the Defendant would have to install and send the tamper) was broken, and that the message “mal rick” was damaged.

As the defendant demanded repair in response to this, the plaintiff would bear 50% of the repair cost only for the "malr" issue.

The Plaintiff demanded the Defendant to return the medical device of this case while cancelling the agreement on the instant sales contract. However, the Defendant refused to return the medical device of this case by demanding twice the down payment.

C. On November 27, 2017, the Plaintiff sent text messages that the instant sales contract was rescinded on the grounds that the Defendant did not pay any balance.

On November 29, 2017, the Defendant considered a text message to return the down payment and bring the instant medical device. The Plaintiff demanded the inspection of the equipment for the instant medical device and the delivery of each letter that the Defendant did not use the equipment, and the return of the down payment.