The following is said with compassion and respect, and understanding of your frustration:
1. Find out who the Mortgage Holder is today.
As said below, the Mortgage has probably been sold to some other company.
Toss the other mail, and ignore the bogus phone calls.
2. Retain a Real Estate Attorney. Have her / him make the Initial Contact with the mortgage holder.
3. As suggested by a previous poster, do a serious assessment of your financial situation.
Three payments behind, and out of work...
You may want to think about getting out of your home now, via a Short Sale.
4. For what little consolation it may be worth, there are Millions of people in your shoes.
Don't take it personally - times are tough all over.
Best wishes to you,