Paypal should close it soon if not here are some more steps to follow.
Send in any and all screen shots you have taken when talking to the person and giving them the items. This is why screen shots are important. If you did not take screen shots then refer below.
Call in to paypal and ask them why are you getting charged back, if they tell you because the buyer opened a dispute say I have already given them the virtual items, as the statement says in my terms this user can not open disputes regarding this case asI have already sent the Virtual goods. Be polite and calm when saying this, you will probably get the run around a couple times, see if you can talk to the manager. Keep calling them every day or second day and explain the same thing over and over eventually they will put the money back into your account.