Stubborn wall plate

[Ltrain]

I'm trying to change my shower head, but my old wall connect points downwards with a sturdy wall plate I can't remove (see pictures). I've tried to jiggle it loose around the black rubber, but it still feels very firm. Is it attached to the tile permanently? Or should I just use more muscle?

Also, any advice on removing the shower bar? Equally stubborn with no screws or caps in sight.

 

[Geofd]

I'm guessing that piece up against the wall threads on also

 

[breplum]

for the wall elbow, I usually use the shank of a 4 in 1 screwdriver placed in the opening.
sorry, don't recognize the bar...

 

[skeezix]

Could be glued on...

 

[TomFOhio]

I think the black piece is fastened to the wall and the chrome piece snaps on to it.