If you think that your Mac Address is banned then follow this tutorial, it will guide you step by step on how to successfully change your mac address
You must login or register to view this content. . But I highly believe you're console banned, this means you will need to get a new console ID. Remember: Console ID Selling/Trading/Buying is prohibited on NGU. So you'll have to find someone outside of NGU to sell/give you one. Good luck.