Am I justified in my frustration?

I have been trying in contact with the seller today. I don’t know if he saw this thread but I do know he has integrity. He PayPal’ed me a hundred. He obviously didn’t think it would be in this bad of shape. He still wouldn’t answer how long the Diff was exposed out in the elements but he did admit that it was sitting outside with one axle removed before he got it and put the other axle in it. It WAS long enough for it to get thoroughly rusted and become food storage for mice though. Who knows how many times it got rained on before he reinstalled the axle.
When I first contacted him he didn’t believe a word I was saying then I sent him the video and pics.
He either started feeling guilty or maybe he just wanted me to go away.
If this thing comes apart undamaged the $100 will go to a ring and pinion cause I can tell by looking through the fill hole the pinion is rusted to **** and can’t be reused.
I do have an S60 that is A-body spec in my mini tubed 70 ‘cuda I’ll use if the 8.75 housing end or 489 case is shot.
Been wanting to do a 9” floater in the ‘cuda anyway.
I’ll give the WD another day try the chain and weight idea, and last resort is back to pulling on it with the truck. Maybe get a gallon of PB Blaster too.
What I WON’T do is put the one axle back in and sell it as a “good rebuildable core”, LOL.