Help any answers

just had a brand new bath tub installed and my went to install the greenboard arouund the tub area and the [i]tub is not level the front of the tub is down approximatly 1 1/2 inches below th back of the tub whichis going to make for installation of tile looking unprofessional. My help question is. Is the tub rim to be level? I have a call in to the installer. This is why all my remodeling has been done by myself. At least i know it is down right and if not its my fault and i have to make the corrections.

I have already replaced windows and remodeled / gutted the den and the one bedroom.