Is there a way to restore some products that are no longer available, such as the Creative Pack?

If you have purchased products that are currently discontinued, such as the Creative Pack, please click the Restore Purchased Item button on the plan review screen of MediBang Premium.

The item will be restored if you’re using the same store account as when you purchased it, and you’ll be able to use the item as before.

https://medibang.com/faq/#faq_premium10