I had both my old and new 3ds systems banned and I found this video. Hopefully it doesn't violate the rules but even though its in french, its easy to follow and it got my 3ds back online.
@Xdqwerty, to answer your question, they're a fusion Brit-pop/J-pop/electronic band with a woman vocalist. Flamingo is hands down their best known song but they've got a ton of other really good songs