Firstly, if you still hold your merchandise, you are in charge of the situation.
If you still have your goods in your possession, you cannot get ripped off.
So type YOUR rule in "no goods are released until the money is released to me by PayPal"
You can emphasise this rule to the wannabe buyer that "you pay PayPal and PayPal pays me"
But of course send the goods as soon as you get the money INTO YOUR BANK.
I ALWAYS get what I call 'double registration' I make sure I get the reciever's signature form
The post office (of all countries) call it Delivery Confirmation and the buyer's sign the form which is posted back to you. Yes, it costs more but not as much as a buyer's charge back.