Please follow below steps to change your mobile phone number on ICS services:
1 - Click here and login your NTTGame account.
2 - Under the MY ICS tab, click on Change to Mobile
3 - Select your country code  and input your new mobile number.
4 - Click on Send Code button. Please do not forget that you need 5 NPoints for the process.
5- Confirmation Codes will be sent your both old and new phone number.
6 - Please input AnyOTP Code, (OLD Phone) SMS Confirmation Code, (New Phone) SMS Confirmation Code and click on ''Complete'' in 300 seconds.
7 - Your registered phone number in the ICS system has been changed.
Please do not forget! You can do this only once within 24 hours. If you have lost access to your old phone number, do not hesitate to contact us via our support system.