I took this shower valve off because it was being odd and it took 2 mins of fiddling to get no water to come out. The whole assembly just pulled out very quickly with no tools, and I can tell there's something wrong because I can hear a part rattling around inside. I tried gently pulling it apart first to no avail. Then I found a diagram showing there should be a 2mm hex nut in the triple spoke head, but there isn't one there at all. I then looked for replacement parts, but all of them just have the metal bits, and not the black plastic with brass spline inside it. What is the best way to get this fixed? More on reddit.com

No expert here but that looks like a work of art More on reddit.com

picks, hooks, duckbill pliers, twisting motion side to side. Good old fashioned cuss words, and if all that fails, a few good whacks on the face of the valve w your purse should loosen it right up. Theres likely just mineral buildup and itll take some finessing to come out. Dont be afraid of it breaks in the process. Take it out in pieces if need be. Next time dont turn off the water just use a flat screwdriver and turn the two stops on either side of the valve. More on reddit.com

You probably cracked it, you’ll probably need to call grohe to get the replacement parts. More on reddit.com