chop someone off
Fig. to stop someone in the middle of a sentence or speech. (Abruptly, as if actually chopping or cutting.) I'm not finished. Don't chop me off! The moderator chopped off the speaker.
chop something off (of) something
and chop something offto cut something off something, as with an axe or saw. (Of is usually retained before pronouns.) We chopped the dead branches off the tree. You should chop off the other branch.