If your shower head won't turn off, the "on/off" switch is not working, and water keeps flowing even in the "off" position, we will look at how to fix this issue.
Connecting the showerhead to the handle
The shower handle, the part with the "on/off" switch, only works in one direction. If it is installed in reverse, the switch will not function properly.
This is how the showerhead should be connected to the shower handle:
Note that the "on/off" switch is at the top of the handle, closest to the showerhead.