Dispute Investigation Open : Never Solved for 10 Month, and Middleman never respond

Hello All, I'm writing here because tired already, It's been 10 months since the case started, and whenever I asking about an update, the middleman didn't reply. I choose to sell here because as mentioned, seller benefit that this site covered chargeback protection, details case is, buyer buy my yu-gi-oh duel links account $650, after he login and moved data, he said he can't login and want to cancel order, I proved that I have video of the login process till submit to 3 ways conversation works and fine, he said he only want to makesure by lying. After that he keep arguing and left, I heard from vip middleman he do chargeback and playerup banned his account, but the problem is I lost my account and never get my money, and order status still "Investigation Opened" until this day, I believe middleman didn't care because no progress at all, and I'm asking about playerup statement of chargeback protection,

I'm stop uploading and selling in playerup before this solved, or if never solved at least I say what I want to say, so other seller can know, Thanks