I think it would be good to consult a lawyer about your situation. On face value your situation could be misconstrued as having obtained your Green Card fraudulently. I have no personal experience in this area, but I think there are companies that somewhat create fictitious jobs for people to obtain Green Cards and they could look at your case and consider that this is what happened with you. I know that a lot of honest applicants got caught in a situation where their employers put them on the bench during the downturn that started in 2000. However, your situation seems to look worse because you never worked for your sponsoring company. Anyway, my best advice is to consult a lawyer. I don't mean to scare you, but in your situation I think it is best to pay for professional advice than just hope for soothing words from this forum.
My 2 cents.