Here are the steps you follow to win every dispute. This is when you're dealing with virtual currencies.
1) Get an email from the person who is buying the item from there VERIFIED Paypal email address. What you want them to include is a filled out order form, you will send this from your REGISTERED paypal email.
Include all the item specifics. So say if you are going to be selling someone a Bitcoin, the order form would look something like this. You can also give them a random order # which will just add onto the evidence.
Product:
Bitcoin Address:
Amount of Purchase:
Is this purchase for Bitcoins (y/n):
2) If you can you need to get some other form of proof such as ID or there phone # attached to the Paypal account. You call the number and ask if they're okay with the payment and you're just making sure etc.
3) Screenshot all the chat logs and your transaction being sent to the BTC address
4) If they reverse the payment upload all the screenshots and information to Paypal Resolution center
I've had disputes filed against me three or four times and using these methods I have won all of them.
If they dispute the charge with the credit card company, you will loose. If the account is hacked/stolen, you will loose.