Missed the biggest part of the show due to a technical problem with my TV.
What song throughout the show did Ben and Fleur choose to sing

Man in the mirror and uptown funk, you can watch it on youtube.

Ben did Man in the Mirror, and Fleur did Up town Funk.

The X Factor 2014 Live Show Acts Also Performed "Flash Dance"

Olly Murs & Demi Lova did their duet of "Up"

One Direction did "Where Did Broken Hearts Go" with Legend Rolling Stones Member Ronnie Wood on Guitar

Sam Smith did "Stay With Me"