# A severe vision has been given to me

This can be stated in active form. Alternate translation: "Yahweh showed me a troubling vision" 

# the treacherous man deals treacherously

"those who deceive will deceive"

# the destroyer destroys

"those who destroy will destroy"

# Go up and attack, Elam; besiege, Media

"Go up and attack the Babylonians, you soldiers of Elam; go and besiege the Babylonians, you soldiers of Media"

# Elam ... Media

Here "Elam" and "Media" represent the soldiers from these places. 

# I will stop all her groaning

Here "her" represents all the people who are suffering because of the Babylonians. Yahweh will cause them to stop groaning when he sends the armies of Elam and Media to destroy the Babylonians.