How To Dispute Properly?

Okay, so I sent this guy $55 for a League of Legends account and now he suddenly vanished, so I'm going to dispute. I was wondering how to successfully file a dispute with Paypal. Like what do you select as a category of your purchase and what to write in your message.

i dont know if im right but i think u dont have buyer-protection from paypal if u buy not-material stuff?

This kid tried to scam me with a league of legends account I was selling.

I will win the dispute and own this scammer.

He's a complete liar. I paid for the account and he never sent the account after he received the payment. I waited all day for him, then as soon as I sent the dispute he responds. I actually posted the conversation we had and I will screenshot it, let you view my screen, or record it, anything I have to. He's a scammer. Hopefully he still had the money when I called Paypal and they froze his account. If you check the conversation he was trying to tell me the money was already gone, he's an idiot.