Question about PayPal

My account is not verified and it's limited at the moment, but i'll link my CC today... the thing is, I had $900 dollars on it by selling Rsgp, but now I have $500 dollars since the buyer is saying that the payments were unauthorized, but w/e.
My question is: after linking my CC into my PP account and removing the limitation it has, what happens if I draw all my money and then this person continues saying that his payments were unauthorized (the $500 left that I currently have)? That would leave me with negative balance... can they take the money from my CC? If not, then what would PP do about this situation?

Thanks for your time guys, I do really appreciate it!

EDIT: Also, can I remove my CC from my PP account after drawing all my money?

 

No dupe threads please. Should be here, anyway: http://sythe.org/help-requests/