Bathtub Installation

Hello:

Had a bathtub installed. The tub was fastened to the wall stud with some type of nail at the top of the flange .
Now the tub is loose & creeks real bad when taking a shower.
I'm told the installer should have used some kind of poxy / glue on the bottom of the tub. No glue was used to stablelize the tub. Where did the installer go wrong?

Thanks for your help.

Glen Hartsock