If the extractor moves, then it has to be a problem with the chamber or cartrdige to make it stick that bad. I'd call them and tell them exactly what you did, be nice and I'm sure they'll resolve the problem.
About a year ago, a GBO member was at the range shooting his .243 Handi, his friend was there shooting a 7.62x39 Russian with him and inadvertently loaded a 7.62 round in the .243, the gun went bang, but the case stuck and they couldn't break the barrel open, H&R fixed it for him, but it needed a new barrel.
Just be honest and nice with them, that's my advice. It may be the ammo was overloaded too, I don't know, but give them a chance to make it right for ya, there could be a defect in the chamber, maybe it's bored out of alignment to the bore. Since the cartridge didn't go all the way into the chamber, the brass could have been too long too, not sized properly for your chamber.
Tim