I too purchased the ezt3d printer and had problems, and also received a refund as the vendor did not seem capable or was unable to fix it… The problem was that using the auto levelling ,after adjusting the extruder at the centre position when it moved to the outer positions it was always 2mm above the bed. If I corrected that on repeating the exercise it hit the bed at the centre. I can only think that there is an error in the program but there is no provision for any access . Has any one been able to solve this ??