Why my Twitch handle NOT mine?

Hello, new here and to log in I used Twitch. But the username on your website has me as BlueBellBike...something or other and it wouldn't allow me to move forward if I didn't except the page info. I need it fixed to me- GoDeZzOfWar. How do I do this? Thank in advance. Nat R. Molina AKA GoDeZzOfWar