Still can be reversed on paypal, and even yet, your credit card company
![Sad](https://bitcointalk.org/Smileys/default/sad.gif)
on what basis? the paypal payment landing page stated that sending money via this way does not offer a buyer protection.
You can't open a dispute if you did not receive your object, because basically it is not designed to exchange object.
But you can still open a dispute if your account got hacked and used without your notice, which is obviously what people do.