Hello it's Natara.
We apologize for causing you confusion with the ending times of the two events, as the countdown in the game was misprinted. Due to this, we have heard several users say they could not exchange goods.
The original event time was written correctly in the Events section and was supposed to end at 12:00pm today 28th (GMT+9). However, considering that we have caused confusion by the time output error we will extend this one more day to 29th 12:00pm (GMT+9).
*This does not include additional event items.