"What stinks to me is that you KNOW they had to know they did that, and just didn't own up to it. That type of stuff irritates the heck out of me. I would imagine you could use some type of silicone in the holes, but I would be tempted to have something mounted via epoxy or liquid nails on the outside for the silicone to adhere to. I don't think just filling the holes will work all that great. Like everyone says, the easiest thing is to replace the unit or demand that they do, but hey, it's not our money right?