I'm trying to think ahead and think this through. When you get a bound drone, you ask DJI to reach out to the owner. DJI will do that on your behalf and ask the previous owner to unbind. If the owner does not respond, DJI ends it there, right? They don't ask for receipts and stuff, correct?
What's to stop someone for faking a receipt? If the owner has died, how can DJI confirm the fake receipts? It would be way too easy for people who steal bound drones to claim they bought it from a person who has died (which is why they can't respond), here are my receipts (which you cannot verify), please unbind my drone. That's so lame. DJI doesn't release private details but my thoughts were if you left that estate sale with a copy of the cert and you sent that to DJI, maybe that would trigger it or help in some way? You know, something they could verify? Public records?
The whole DJI process is a black hole and it's hit or miss which is why I always suggest buyers to completely avoid it or buy at their own risk and peril with no expectations. I've seen a few hits but I've also see a lot of misses (and tears)0. I know this is all new to you because I think I recall you asking the question once upon a time "What is this all about, never heard of it?" so here we are....and it keeps popping up almost daily. Trying to help.....