[Lorewalker]

No idea how ebay's new managed payment system plays in this but here is how paypal addresses refunds:

You can request a refund of a completed payment by sending the seller an email. Ask the seller to go to the Transaction Details page for your transaction and click Issue a refund.

You can request a refund up to 180 days after you pay for your item. If you sent a payment, but it's still pending, you can cancel it on your Activity as long as you see the "Cancel" button next to it. If the payment isn't claimed within 30 days, it will be automatically refunded to you.

If your seller doesn’t agree to refund your money, you may be able to open a dispute in the Resolution Center if you didn’t receive your item, you received something that doesn’t match the seller’s description or your payment was not authorized.

If you purchased something and would like a refund because you haven't received it, or it's not as described, you can file a dispute in our Resolution Center to start the process of getting your money back.

You have 180 days from the transaction date to initiate a dispute.

If your eBay payment is complete, but you didn't receive your item, it's not as described or the auction got canceled, you'll need to file a dispute. You can do this in eBay's Resolution Center or the PayPal Resolution Center.

If you feel the transaction was unauthorized, please visit our Resolution Center to file an unauthorized transaction dispute.

There are 2 kinds of disputes you can file:

Item Not Received – You bought something, but didn’t receive it. (Wait at least 3 days from the transaction date to give your seller enough time to ship the item.)
Significantly Not as Described – You received an item, but it was significantly different from the seller’s original description. (You might have to pay return shipping costs, but may be eligible for Return Shipping on US. Activate Return Shipping on US before filing your dispute to qualify for the benefit.)

If you sent the payment using a debit or credit card, the refund will be sent to the card used. It may take up to 30 days for the card to be credited. If you sent your payment using a bank account and the payment is canceled, it will be refunded to your bank account.

***Bank funded transactions: for cases in which a refund is requested or processed shortly after a purchase is made, we will make an effort to cancel the transaction, so you are never charged. If we’re unable to cancel the transaction, then a refund will be processed. Your funds should be credited to your bank account within 7-10 business days.

In addition I think you can go around paypal by going directly to the bank issuing the credit card and open a dispute that way. If that is done however I believe you waive your rights to filing a dispute with paypal directly should it not work out.