1. The Defendant (Counterclaim Plaintiff) paid KRW 391,500 to the Plaintiff (Counterclaim Defendant) and the Plaintiff’s objection thereto from April 24, 2014 to January 11, 2017.

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. Basic facts

A. On May 30, 2007, the Plaintiff is the owner of the above 3, 4, and 5 floors, which completed the registration of ownership transfer with respect to the 3, 4, and 5 floors among the 1st underground and the 5nd ground-based buildings (hereinafter “instant building”).

From around 2006 to December 2015, the Plaintiff operated a telecom with the trade name “D” from 3, 4, and 5th of the instant building from 2006 to 3, 4, and 5, and operated a telecom from January 2016 to 200.

B. On May 29, 199, the Defendant is the owner of the second floor above, who completed the registration of ownership transfer with respect to the second floor (numbered by 201 and 202) among the instant buildings.

From around 1999, the Defendant leased the instant building from around 201,202 to the wife E with management such as the conclusion of a lease agreement and the receipt of monthly rent.

C. The sectional owners of the instant building are four persons including the Plaintiff and the Defendant. From around 2003, the first floor 101 and 102 were owned by F, and G completed the registration of ownership transfer on April 9, 2012, and is currently operated as a cafeteria with the trade name “H”.

On March 5, 2004, No. 103 of the first floor, I completed the registration of ownership transfer, and around that time, J, the husband of I, has operated laundry with the trade name "K".

[Judgment of the court below] Facts that there was no dispute over the ground for recognition, entry of evidence No. 1, the witness J, and the purport of the whole testimony of L

2. Determination on the main claim

A. The Plaintiff, on behalf of the other sectional owners, paid both the water supply and sewerage charges imposed on the section for common use of the instant building from January 2006 to December 2008. As a result of the settlement of accounts, the amount paid by the Defendant falls short of the amount to be borne by the water supply and sewerage charges calculated in proportion to the Defendant’s total area, the Defendant’s share of KRW 3,288,654 is the Plaintiff.