As this is your first time purchasing NCoin, you are not be able to purchase certain items from the in game store while your NCoin payment is under review/evaluation. While you may have already received your NCoin in game and can purchase some items, it could take 24 hours for you to be able to purchase certain items.
If you are receiving the following message when attempting to purchase items in game, you will need to try purchasing the item later (24 hours from your NCoin purchase):
“The transaction cannot be completed until the NCoin evaluation is finished. Please try again later. Please visit the Support website for more information on the evaluation.”