You were banned for ownership of clearly duped legendary keys, which falls under Rule 2 (Bug Abuse). You say you didn't give them to anyone and "they" didn't let you know. I feel like it's pretty much common sense that duping is not allowed, but it is in the rules which can be found right here on the forums for future reference. And of course, not knowing that it's illegal doesn't mean it's justified, imagine how many people we would have to unban if it did though ?
As for the appeal, I don't find it appealing enough and you didn't even use the correct template.