HELP! Privacy and changing profile name on leaderboards

My user name that appears on leaderboards is my full legal name and I dont know how to 1. Keep my name off the leaderboard, and if thats not possible 2. Change my user name. I tried changing my name in my settings and it did not change on the leaderboard. I am concerned for my privacy and customer service has been completely unhelpful after 30 minutes. So now I'm here looking for answers... Thanks if you can help.