If indeed you were married, and your spouse did not sign the mortgage, this is a technical error that may prevent the bank from completing its foreclosure. Obviously, you need to have an attorney review the records and file an answer in defense of the foreclosure within the 20 day period or you may lose your home by default.
You respond by Answer, to the Complaint. You should get an attorney to help you do this, either by hiring an attorney, calling legal aid and seeing if you are income qualified, going online to the County Clerk's Office for your County and reading about help within its foreclosure division and finding an attorney online through your local bar association.
Since you haven't paid in three years, which probably means the bank has also paid your taxes, forced insurance, HOA fees, if any, it doesn't appear that you are going to be able to afford to pay arrears to keep the house, if you want it. To find out all your options, you need to get an attorney and also to protect yourself by submitting an Answer to the Complaint and lis pendens.
This communication is not intended to create an attorney/client relationship. It is always recommended you consult an attorney in person to discuss your case. Leonore M. Greller, Esq. is a Supreme Court Certified Civil Circuit and Family Mediator and a Qualified Residential Mortgage Foreclosure Mediator and Arbitrator.
It is essential that you contact an attorney who can respond to the summons and complaint within the first 20 days from when you were served with the summons. You may have some good defenses to the foreclosure, and there may be some alternatives to the foreclosure also. You may be able to save the home, if that is your goal. I would recommend speaking to an attorney about your situation immediately, as time is of the essence here.