The attached ZPL prints one, then prints the next, cuts and presents.
It is possible they may have set the printer to Black Mark but did not run the calibration routine.
 
The media needs to be loaded in the orientation shown in the attached photo.
 
Files attached and should be run in this order.
Norway Black mark media setup.zpl     This sets the printer to Kiosk Mode, Black Mark, Print Speed 6, Print Width 640 dots (80mm) and kiosk variables.
Norway Black mark media Calibrate.zpl     This calibrates the printer for the specific media
Norway Black mark media01.zpl    This prints one, then prints the next, cuts and presents.