Let's say I buy a fancy watch from a guy on the street, hot but I didn't know it. The long arm of the law somehow leads to me and the watch. It would be taken from me and I wouldn't get my money back. I have no recourse to go after the guy who sold it to me. He was a complete stranger.
That also doesn't strike me as entirely fair. If nothing can be gotten from the person who actually did the stealing, then the person who lost the stolen item and the person who bought it should somehow split the cost IMO.
One thing that is very interesting is that the OP was trying to
sell a senior account for .25
BTC. If marcotheminer is interested in keeping the account then he could potentially send the OP some amount of additional funds to "buy" the account so that it is "no longer hacked".
I am not sure what a fair price would be though, the market is not good and both parties are at least partially at fault (assuming it is in fact hacked), I would say that the .32
BTC that he essentially bought it for is a lot less then what it would sell for.
Another option would be (if both parties agree) to auction off the account and each party would receive a portion of the proceeds depending on the sales price. This would result in likely both parties taking some kind of loss and letting the free market determine just how much each party gets. It is also likely very similar to what marcotheminer would have done if the loan was not repaid
In regards to your last suggestion, you have to remember that most people have some sort of attachment to their own account and don't just view them as commodities. I doubt yussuf would agree to this, although he could in theory bid on his own account and pay half of the bidding price.