HELP!!! the buyer is going to open a dispute

yes, I mean $710-paypal fee, I received around $680.
This bidder sent my the confirmation # yesterday. and it shows the item has been accept yesterday. My problem is that I will leave for vacation tomorrow morning, which means I will not be home waiting for the package.
Do you think it is safe if I track the item online while I am oversea, and I saw it shows delivered. and I just refund her money??
What if she sent me a empty box??


Yes, I think she meant because of the fees.