Greetings, This is MIR4.
We have confirmed that there is an issue to be checked on some of the in-game products purchasable through the Shop and took preemptive action to make them unpurchasable temporally.
Our team is doing our best to find out the cause of the issue and currently working on normalizing related systems.
Please be noticed that the disabled products will become purchasable again as soon as the fix gets done.
Moreover, all of the products are being examined at the moment, and so we kindly ask for your understanding that there may be more products that might become unpurchasable if such an issue persists.
We sincerely apologize for the inconvenience and we will do our best to provide a stable service.
Thank you for your understanding and cooperation.