How to Redeem Coupon Code?
How to Redeem Coupon Code? 
1. Log in to your GNJOY account.
2. Click on your icon in the top-right corner and click "Redeem Code".
3. On the "My Page" site, click on "Redeem Code" and enter the appropriate code.
4. Click it, then enter your code number and click on "Redeem". It will show "Code applied successfully. Please check your history". Once done, you should receive it via in-game mail system (RODEX) instantly.
Remark: Any attempt to enter the same code will display an error message, indicating that the code has been redeemed previously.