Scary situation in my shower when this thing deattached from the wall

I'm trying to figure out how to fix this thing permanently. In my shower the hand shower attaches to this big pole, the pool itself attaches to the wall to places one at the top and one at the bottom.

At the bottom it has detached from the wall and if you pull the hand shower off of the wall it will pop out while you're in the shower and cause a scary situation.

I do not know how to fix this but I am an amateur. Can you give me any advice???

Video below: https://imgur.com/a/1OQ0KJ6