Where would I get a signed message from?

There are only 2 posts on this account and I don't see what value it would serve as I'm not going to pretend like I am the original owner. I am not.  I bought it. I didn't hack it.

There was a sale thread.  I bought the account.  It is being used as a collectible/novelty account.  Users should not trade or trust this account.

It could be that the original owner decided to come back and sell the account.  It could be that the seller hacked it, but that doesn't mean that I hacked it as your feedback seems to point towards.

Why not just leave feedback that accurately portrays what has happened?

Leaving "probably hacked" gives the wrong impression and the only damage that you are doing is to me.