I don’t care anymore 
He may not have gone about resolving the trade issue in the best way, and he may be young, but does that really matter? There are plenty of young kids on this forum, he does not need to share his age if he doesn’t want to.
The fact of the matter is that you sent him a b-grade without disclosing it was a b-grade. You tried to delete your account to end communication. You are in the wrong.
There’s a simple solution for you two - You refund the money, he sends back the yo-yo, and you two avoid trading in the future. No need to drag it out.
I don’t care anymore.
Right. What we DO KNOW is that a thread was made claiming you didn’t describe or had misrepresented the condition of a yoyo you sold. We ALSO KNOW that you attempted to delete your account shortly thereafter without responding here.
It sounds though like you’ve corrected the situation. Thanks for that.
UPDATE: Yoyo returned by buyer, missing axle in return package, food or some sort of goo/crust on yoyo. Yoyo of topic recently sold to another player, player happy and stated no vibe, small, unnoticeable marks. Gladly refunded original buyer’s money.