Most people voluntarily surrender their house at some point to the bank.
A few people resist the bank attempts to steal their house and resell it by going into the court system. Before you go to court, it is generally considered polite to try to resolve your issues by contacting your state Attorney General, the CFPB, your representative in Congress, legal aid society, and anyone else in the regulatory business. This is very time consuming and will require a lot of reading, writing, talking on the phone, and most people won't do it.
There is no one other that yourself who will do this work. It is very easy to give your house away. It is very difficult to keep it. The internet is now overflowing with reports of the experience of people fighting their mortgage companies. Most of them are stories of their unsuccessful efforts. There are a few successes.
To familiarize yourself with the issues, I recommend three good movies to watch, available at Amazon or Netflix or many other places.
The Big Short
This will cost you $30 and occupy six hours of your time.
If you decide to fight your bank, you should know that they all typically employ a crew of the best young lawyers in the industry, who work every day their allowable twelve hours for billing purposes, and continue to work all through the night earning bonuses and writing the necessary papers to influence you to surrender your house voluntarily or steal it by decree of the court. Their billing is paid up to date by their client, who finds it of no burden to expend 50 million dollars per quarter to pay hired help or pay whatever fines necessary to continue to accumulate 50 billion of free property. Public companies report their success quarterly. Private companies typically do better.
Now you will have to read the book Win Your Case by Gerry Spence. This will mentally prepare you to Win Your Case.
If you fight, your chances are actually pretty good, because their case is built on sand. You have Truth, Justice, and The American Way.
These are the records of a homeowner who has been in contention with a mortgage servicer since 2012, asking very basic questions. We are still in litigation today, asking very basic questions, and wanting to remain a homeowner. Five percent of American homes are foreclosed every year now, and homeowners become renters. Correspondingly, five percent of homes change status from 'owner-occupied' to 'investment property,' with government financial support. We are enriching investors, and dispossessing owners. BTW, did I already mention attorney fees?