If you purchased using iPad or iPhone through iTunes: You may need to Restore Purchase after changing device or reinstallation. Please open Pubu App and tap to open sidemenu, click Settings - Restore Purchases, you can continue reading after the success message.
If you purchased using phone billing: Please make sure you have enabled phone billing with your phone operator, it might be blocked by the operator.
If you purchased from convenient store kiosk: Please provide your order number and receipt to the Support team to verify your purchase.