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It's not that the same problem happened to me it is that you're profile is a child profile you need an adult profile so make a new one like I did to play games that my other profile couldn't play

Many people take advantage of injustice coin hacks and cheats as well but sometimes those take a bit away from the fun of the game leveling your own team and winning the game and having a feeling of accomplishment. To defeat this my work around is using a WBID account with full unlocks to get a few heroes that will help with a starting boost rather than make the game easy and boring to play. Getting a WBID account with full unlocks online is terrible hard to find. Free Injustice WBID accounts that have been posted all around on the internet mostly do not work as other person change the passwords to the accounts.

Are you currently connected to Xbox Live/the Internet? If you accidentally got disconnected or you don't at least have an Xbox Live Silver/Free account and are connected to the Internet it won't let you select it.