Not sure what to say to you. I'm not a gun smith, but very good at fixing stuff. If I can see how it should work, and see how it is not working, then most likely i can fix it. Really need more info from you. But from what you have said i think little of a gun smith that cn't figure out why a gun is not working, unless it was working for him. It is my understanding KT does not try to recreate your issue, but just replaces any part that my need it and then test fires the weapon several times.
Need more info from you. what ammo do you use? Etc. Describe what is not working in detail. It could be a lot of things having nothing to do with the gun itself, but how it is being used, Etc.
Most work great out of the box, some needed lots of work. I love mine. It is a daily carry. But it was one of those troubled child to begin with. But as i did my research before buying I knew that could be a issue at first.