1. The plaintiff's appeal is dismissed.

2. The costs of appeal shall be borne by the Plaintiff.

Purport of claim and appeal

The first instance court.

1. The issues of the instant case and the judgment of the court of first instance

A. The key issue of the instant case is whether the Defendant’s demand for payment of KRW 3,889,350, out of KRW 10,396,278, which was not recovered to the Plaintiff, is an administrative disposition subject to appeal litigation.

B. As to the judgment of the court of first instance, where an insurer or an insurer organization urges the payment of unjust enrichment or additional dues and then urges the same contents again, the first demand is an administrative disposition subject to appeal litigation as it is a collection disposition. The same demand thereafter is a collection disposition, which is a premise for disposition on default, and is merely a mere peremptory notice under the Civil Act, not a demand demanding the interruption of extinctive prescription, and does not directly affect the rights and obligations or legal status of the people (see Supreme Court Decision 97Nu119, Jul. 13, 199). Thus, the demand notice of this case cannot be deemed an administrative disposition subject to appeal litigation since it was made more than the first demand, but it is already made more than several times after several demand notices, and thus, it cannot be deemed that the additional dues under Article 55-2 of the former Medical Insurance Act are an administrative disposition subject to appeal litigation as a matter of course arising from legal provisions without confirming the disposition (see, e.g., Supreme Court Decision 2005Da15284, Jun. 10, 2005).

2. In light of the court's decision and the circumstances stated by the court of first instance which cited the court's decision of the first instance.