my account has been duplicated and i'm stuck in the demo

when i tried to add a mod to my Minecraft my account just duplicated itself (both still keeping the same username). when i tried logging in with the new mod i was stuck in the demo. i then tried logging in with vanilla minecraft and had the same problem. i then clead my 'mods' folder in .minecraft and the problem continued. i treid switching between my two duplicated accounts and both accounts had the same glitch. Please help me fix this.