If the items are in your warehouse you're gonna have trouble to get all your money back.
You can try to return as many items as you can, but usually you only have 7 days to do. On top of that, some agents charge a service fee after a certain number of returns. And then you have to pay for the domestic shipping. That means you will never be able to recover the full amount.
Then the next step will be to withdraw your money to your paypal.