My dear friend Geace,
Sorry to hear your story. Don't keep your hopes up with your visa unless you find a new employer who can sponsor you before this 187 abolishes only if you have 3years of experience at present in your nominated occupation but I think it will be more tough for you as you had spend a lot of money already.
First you should have withdrawn your visa the moment you came to know about your employer bar. Secondly doesn't matter who the lawyer is no one can challenge immigration from the bar that was imposed on your employer. Your new agent has absolutely misguided you. They definitely knew your nomination will be refused one day. Jason knew you being innocent and a good opportunity for him to fetch money within 5months from you. I will suggest you to write a review on their website to make others aware about the fraud lawyer like Jason who believes in making money fast.
You can write a letter and explain your situation to DIBP but DIBP will not consider your case anymore as whatever happened its between you and your employer. Immi has no role to play in it but just before giving up try writing them a letter and explain you were no where at fault.
One of my friend's friend got refusal for the same reason as well. He is working now for a new employer after refusal and trying for sponsorship from him. So all the best for your future. I am really sorry for what happened with you. Please don't rush while hiring a agent again.