Sounds like you have had a terrible experience and I'm so sorry this is happening to you. I would suggest that you contact your Realtor and your real estate attorney. Ask both him or her to refer you to another mortgage bank that might be able to give you a second opinion on the current situation. Good luck and I hope it works out for you.
I know that a loan denial at this stage of the game is crushing after having invested time, money, and energy into a purchase.