1. Of the plaintiffs' appeal of this case, the damages for delay calculated by applying the rate of 5% per annum from August 9, 2006 to August 15, 2013.

1. Whether the plaintiffs' damages for delay in the appeal of this case are legitimate

A. In the judgment of the court of first instance, most of the plaintiffs' appeals against the damages for delay in the judgment of the court of first instance concluded a sales contract with the defendant for the rental apartment of this case from January 2006 to February 2 of the same year, and the plaintiff E concluded a sales contract at the latest August 9, 2006. The defendant's damages for delay in unjust enrichment that the plaintiff E received from the plaintiffs for unjust enrichment in excess of the legitimate pre-sale conversion price for the rental apartment of this case should be calculated from August 9, 2006, at least from the date when the plaintiff E entered into the sales contract. However, the judgment of the court of first instance applied damages for delay in the judgment of the court of first instance from August 13, 2013 to the rate of 5% per annum from August 15, 2013, which is the day following the delivery date of the application for change of the purport of the claim and the cause of the claim.

B. According to the records of this case, the first complaint filed a claim with the purport that “the defendant shall pay to the plaintiffs 5 million won and 20% interest per annum from the day following the delivery date of the complaint of this case to the day of complete payment.” The plaintiff filed an application for modification of the purport of the claim and the cause of the claim, as stated in the “statement of claim” as stated in the “statement of claim” before August 13, 2013. The above application for modification was served on the defendant on August 14, 2013, and was presented at the hearing on August 20, 2013, which was the fifth date for pleading of the first instance trial.

After that, the court of first instance rendered a judgment ordering delay damages from August 15, 2013, which is the day following the delivery date of the above application as requested by the plaintiffs, when partially citing the plaintiffs' claim for return of unjust enrichment based on the purport of the claim stated in the above application for modification, since the date of payment of sale price as to the delay damages.

In addition, the plaintiffs claim the damages for delay as well as the damages for delay.