my iphone restored an old apple id of my sister n laws from 2 years ago. she has passed away and i dont know her apple id password to turn off "find my iphone" so I can fix. apple support says they cant do anything about it

what to do...!?! I was restoring my iphone to factory settings on my computer. I then thought I was going to do another restore after that from a previous backup just so I could retrieve my contacts list. what the computer then did was restore a backup from my sister n laws iphone from 2 years ago. she has since then passed away. I do not know her password to the apple id that is now assigned to MY iphone which means I cannot turn off the "find my iphone option" (which is states MUST be done) in order to fix. by again restoring to factory settings. apple support says they cant do anything about it that I will have to get some sort of court order proving to them that she has indeed passed, and then they can clear the apple id off of my phone allowing me to then reset, restore and backup THIS TIME FROM THE CORRECT APPLE ID BACKUP...MINE!!! AND...they have informed me this can take days. I AM SO INCREDIBLY FRUSTRATED RIGHT NOW I COULD RUN THROUGH A WALL. Does anyone have ANY IDEA as to how i can fix this!?!