Could be okay...hard to say. How much water? If he didn't leave the installation instructions, go on-line and read them...see if yours looks like the instructions.
If you put a straight-edge across the drain, are there any hollows or does it slope to the drain from all directions? He might have put mortar (which is good) under it, but mixed it too stiff and it bowed the floor up. Or, the drain line could be too long, and when tightening down the drain to the receptor, it lifted it.