First thing, which you all ready know I'm sure is don't send anything untill Palpal releases the funds.
Next, only deliver by a trackable shipper with delivery confirmation. Delivery confirmation is free if you ship through ebay plus all your tracking info is automatically send to the buyer. Don't offer codes sent through e-mail.
Ebay has seller protection that is pretty good but you NEED to do every thing by there book. I've made sales for top dollar that ended up being to scam-buyers and/or hacked accounts but because I did every thing by the book I kept the money and Paypal either takes the hit or recovers what they can. One pitfall many sellers fall into is not adding signiture confirmation to sales of I think $249 and higher. If you don't get the sig on those larger sale and there is a chargeback which is a regular scam, you will lose, but if you get the sig your good.