Bank wont give Satisfaction of mortgage.

My wife and I own a condo in partnership with our daughter and her husband. Our daughter/her husband want to buy us out. The condo was paid off in December 2012. The mortgage company claims that they sent the satisfaction of mortgage document to the county recorders office in December. However, The county recorder never received the document. We contacted our mortgage company and they are now in the process of being bought out by another bank. We asked them to re-generate another Satisfaction of mortgage but they say they cant because of the merger. We have been getting the runaround from this bank for several weeks now. They only allow us to speak with their customer service department. They will not allow us to speak to the lien release department. We really need the money desperately. It is the final piece that is stopping the buyout from going through. We cannot close with out it. How can we force the bank to re-generate another satisfaction of mortgage document? How can we file a lawsuit for costing us $$ is the buyout doesnt go thru because of them? Can we sue them for this? Please help me..