Destroyed forgiveness note of debt/ reconveyance

What is the name of your state (only U.S. law)? California
My grandmother gave my father and uncle each a piece of property in 1999,with a small mortgage, a few years ago she forgave the debt on both properties, but the re-conveyance documents were never filed. My father has Alzheimers now and I have power of attorney over him and the property,and my uncle just became successor trustee and has power of attorney over my Grandma. I ask for the paper work and the forgiveness note for my Dad's property it is missing,and someone told me they destroyed it. but I got a copy of the other property forgiveness of debt. They wrote a letter to my attorney saying there was no forgiveness,and are trying to foreclose on me.They don't know I have a copy of there forgiveness note. Any suggestions on what to do? I am getting a new Lawyer at the end of the week,but need suggestions.
Thanks so muchWhat is the name of your state (only U.S. law)?

How much is the debt? A copy is merely that--just a copy, that will give an indication of the similarity of facts in this matter but is not definitive proof that could help you legally.

You posted this question twice--please delete the posting that has no response yet.

It was 109 thousand they added interest and penalties so now they say I owe 136 thousand.
Would the title company have a copy?