I'm a bit surprised they can even pull support for Xbox games. Doesn't MS control all the servers for that, not EA?
EA originally wouldnt use xbox live because microsoft wanted to run the servers. EA wanted them to disable online play for games when the next version was release, and MS rightly told them to fuck off.
Eventually they reached a compromise whereby EA runs their own servers and backend that hooks into the live enviroment. They can do what they want with their servers, and MS dont have any control.