I attempted to replace my 1222B shower cartridge this evening and hope
someone here might be able to assist. When I tried to remove the cartridge
using the cartridge wrench I got at a large home improvement store, the
screw broke inside the cartridge and now I can't get it out. I've tried
using a pair of pliers (like their picture says NOT to do) to try and loosen
it up but I'm having no luck.

Short of calling a plumber, can anyone give me an idea of what to do next? I
appreciate your help.
...Kevin