Both 'are at odds' and 'conflict' would work. The verb 'contradict' wouldn't, because of the word 'with' after the gap.

Thanks guys. I got it now :)

To add to what Su.Ki said, "Their testimonies contradict each other" is a correct English sentence, but it doesn't fit the pattern. Also: conflict/contradict: "conflict" means the testimonies don't agree on all of the important points; "contradict" means they are the exact opposite of each other. A: "First he put on his left sock, then his right sock, then his pants, then his blue shirt. B: "First he put on his pants, then his left sock, then his right sock, then his green shirt. The testimonies conflict with each other, in some details but not all. A: "X started the fight by hitting Y first." B: "Y started the fight by hitting X first." The testimonies contradict each other.