"You took the wrong route" was marked wrong. Should be accepted i would think
Not knowing who "you" are, both "trompée" and "trompé" are accepted in a written exercise. They are also homophones and the trompé variant has been added to the list but it may take quite some time for staff to activate the change. That will only affect the "type what you hear" exercise.
Audio has been temporarily disabled until staff can add this homophone to the diction exercises.
Why not 'You have mistaken the route'? After all, you might not yet be on the road, and you could be looking at a map and have suggested a route. Or is it an idiom?