I can't log in to the game

Hello, please help me, I can't log in to the game, I can log in to my account on the website, but I can't log in to the names from the launcher, writes that this user name is busy.Due to a recent circumstance, I deleted the launcher, and when I downloaded it, I couldn't log in.I changed my nickname SSSS.I don't remember the old one, is it possible to reset something to change I really want to play again (


"Nerds have a really complicated relationship with change: Change is awesome when WE'RE the ones doing it. As soon as change is coming from outside of us it becomes untrustworthy and it threatens what we think of is the familiar."
ā€“ Benno Rice