I've got proofs for what I say.
Where is the proof?
That you hacked it and sold it? Saying that because you are an account seller. Seen on your trust feedback page.
Come up with evidence.
From what I understand in OP, he isn't claiming to have hacked it himself. In summary,
+He originally owned Joeperry (Either through the leak in 2015 as stated or created the account)
I wasn't around in 2015+ He sold Joeperry (Below is a quote to support #Bought back)
Which obviously I bough back in 2018
+ Then it was hacked from him on 14/09/2020.
You could correct me if am wrong.
If my above summary might be true, then there are some questions to these claims.
Haven't sould the account previously,
1. Why going to buy it back?
Did you actually bought it back or you hacked it from the buyer, after you had sold it. Making you the first to have hacked the account, haven't had ties to it. (Suspicion)
2. Could it be that, the buyer later hacked it from you again or it is as you claim. To have bought and then you got hacked?
One of the ways to prove you had at some point owned the said account is as @Examplens suggested.
Now your response to that is honourable,
I might hold keys for some of the above addresses but I don't have any intentions to claim back this account again so it might not be worth wasting the time. I just want to clear the stuff and know how the account was jacked from me by the current owner of @Joeperry.
Although, the forum users cannot be satisfied with just claims. You've got to prove you owned it at some point so users would be weary and just words won't do that.