There is probably a front/back focussing issue with your combination of equipment.

If your camera has already been checked and aligned by the manufacturer but this did not rectify the problem, you can send the unit (lens and camera) to our service team. Within the scope of our capabilities, our service team will then align the lens to the camera. 

The third party camera will not be interfered with in any way during this process; it will merely be used to take a reference photograph.