Originally Posted by Mike Irwin
...There's no way to adequately answer your question without knowing what you purchased.
That is the correct response at this stage.
To the OP, unless it's an antique or a black powder gun, you might have a serious legal problem. It might be best to contact a lawyer familiar with federal firearms law. What you discuss with your lawyer is confidential. What you discuss here is not.
You'll find names and addresses of some well respected California firearm law lawyers here