Plumber help !!!?

If you will look on that brass part right there you're going to see a slot inside that slot is a cartridge retainer use a precision screwdriver to pull the cartridge retainer of course with the water turned off sometimes you can pull the cartridge out of the wall by just clamping onto it with a pair of vice grips and pulling it out steady. Sometimes you'll have to purchase a cartridge remover tool which cost about $15.

There's only room here to give you a picture of the retainer pin that you have to remove you'll have to look up faucet cartridge removal tool to see what one looks like then take it to the plumbing store get the exact same one put a little vaseline on it push it in the hole and put a new cartridge retainer pin in it turn the water back on.

Looks like you have removed the large nut, it probably just needs a block of wood and the give it a whack with a hammer, as it probably has got sealer on it. It should then come free and then you are right.just replace it.

This is a good picture. Bring the picture to your local home center, and ask for help. Chances are that they will be able to set you up with a replacement cartridge, and any special tools you might need, on the spot.

It just pulls put. Once you have it out take it to a plumbing store or hardware store and they can tell you what brand it is and sell you a new one.

You get some pliers and pull it out while wiggling it a little. I cant tell what brand it is.