The Cohhilition

I changed my name on twitch about 8 months ago (i think, not quite sure when), but i am still being logged in with this user name, which is my old name. I tried to sign up again, but it still returns me to my old account.
Hope you can help me with this.
Old Name: ElWorfo
New Name: spicymemeguitar

You have to disassociate twitch account in external accounts