"Turning it to the left" Do you mean counter clock wise? Are you able to turn the cup out far enough to figure out if the cup is cracking or otherwise somehow damaged?

Usually the cup will turn out, although sometimes with a lot of effort during to whole process. Usually only after the cup is out can you discern the shell's condition, unless the damage is evident externally. Do make sure that you're not talking about a cartridge BB unit and it's hanging up on the cable guide fixing bolt.

Did you look inside the shell before you tried to remove the cup? Did you see ball track damage? How are you holding the cup while you remove it? Andy.