If it's anything like a Condor, did you happen to push the button on the forearm that releases it? My buddy shot mine and it did the samething. Just got to make sure you don't have your fingers on the button when you shoot it. I've never had a problem with it. And when they are new, the forearm is real easy to get off. Once they get some use its harder for those kind of mistakes to happen. And when you say it won't open, is it just really stiff? Or actually completely stuck? My gun was really stiff when it was new. Had to muscle it a few times especially when it was getting hot. Now that I've shot it a bit over the last year and a half, it's much more manageable.
Apparently you aren't a fan of these guns. But I must ask, why bash a company on the Internet? Stoeger won't look at your gun any faster. And it's not gonna keep people from buying them. They may not be of the finest quality, but you get what you pay for. And if there's some issues, you just have to wait. I'd be aggravated too, but you just have to keep your cool.
I say if you want a cheap double barrel, a Stoeger is the best choice. I've shot pretty much everything from 8 shot target stuff to 000 and I've never had a problem. I've took mine hunting too. Its the gun I have ready to defend my home and I'd trust my life with it.