Not the reloading expert, but it got stuck on the decapping/resizing die? For me, I've found that necked down cases tend to be more of a PITA than straight walled cases. Brand new cases will run through the resizer easily, but used cases will generally need to be lubed lightly before run through the press or you risk it getting stuck. If you think a case might be getting stuck, don't run it all the way in the press, you'll make things worse. You should try to back it out, if it continues to be stuck, you should pull the decapping pin, then spray the shit out of it with lube. Wait a while, then put the die back in the press and try to back it out again. It should come out.
If it still won't come out, you probably need to keep lubing it, and try to torque/twist it out with a vice grip or something. Alternatively, you could probably clamp the die in a bench vice, then use a correct sized punch or something to hammer the case out from the top (after you pulled the decapping unit from the die. Not sure about using that method though. lol