Being the vice president of your club means being responsible and assisting your president Eunbi with what she needs help with. Of course, there are moments you can't always do well in but you're willing to make up for any of your drawbacks through other means - whether that was to help out with the organising or purchases of props. To make it up for them this time, you volunteered yourself to purchase the props. Except now was definitely not the time for this to happen. She can literally bother you any other day but not now. If you have to fight her for it, then bring it on. You're not about to let a duck win because this was definitely means more to you than for her.