Username hack

So if your open launcher_profiles.json . You can change your username And uuid. Also your email. When i did it I was able login into most online servers with a different username. I was hoping to get paid for this issue since it IS very important . i was thinking a 1000 $ . but if that is to much i just want a couple gift cards to Minecraft website please. Like 50 in all or 100 or more. I would like it that you guys fix it for i don't like the feeling that people can login into my server and steal stuff. please help. I would like some gift cards to . Thanks -Peter