You say that the slide doesn't come far enough back to eject the fired case. Most likely, that's not an extractor or ejector problem.
But how do you know that the slide doesn't come far enough back? What kind of jam are you experiencing?
Does the fired case slide back into the chamber (possibly because the ejector is broken)? Does the fired case pop up, and get caught by the slide with its mouth vertically upward ("stovepipe" jam)? Does the fired case pop to the right, and get caught by the slide with its mouth pointing to the right (another kind of "stovepipe" jam)?
What's the bullet/velocity of the rounds you're firing (too weak to fully move the slide)? Has the pistol always been a 9mm, or was it converted from some other caliber (wrong recoil spring)? Maybe the factory installed the wrong spring—you might e-mail or phone them and explain the problem, and ask for another recoil spring to test.
Here's a way-far-out (and very unlikely) possibility: Does the manufacturer use brazed-lug barrels? The bottom lugs may have broken free from the barrel, and are jamming up the works enough to impede the slide. Take the gun apart and see what's inside.
In order to help, I would need more information.