Well people are confused because you contradict yourself and are unclear in every post. You complained that sound came out of your speakers when you hit the cue button like it should which would lead us to believe you don’t know how cueing works.
How about try hitting the headphone logo cue button in Traktor and take the VCI out of the picture and see if it works? Did you turn the volume fader down (again, do it in traktor if you aren’t sure the VCI is working) and try hitting cue to see if you hear sound? That will answer a lot of questions. Also make sure you have the knob turned in the correct direction, sometimes people mix that up, for this test just leave it in the middle and you can’t go wrong. Report back.