Hello, thank you for your message!
So... since the first time you want to spend kobans, there is a pop-up asking you to confirm. You can click on ''Yes'' or ''Ok! Ok, never show this message again.''
Do you remember clicking on ''Ok! Ok, never show this message again.'' because if you did that's the reason. If you didn't then there's a problem. In that case please PM me with your in-game informations, our dev team will have to investigate.
Other than that, yes we need to implement a max 1 or 2 items with kobans.
Best regards,
Jessie