Miley Cyrus and Liam Hemsworth -- Breaking Up is Easy to Do Over Twitter

Miley & Liam Breaking Up Is Easy ... Over Twitter

Miley Cyrus and Liam Hemsworth are DUNZO -- 'cause there was no going back once Miley unfollowed her ex-fiancé on Twitter.

The hot chick with Liam in Vegas didn't help the sitch either ... we're guessing.