Seems even they don't know their own policies -

Using other programs to address a concern

Buyers can't use more than one resolution method to get a refund. After selecting a resolution process (eBay Money Back Guarantee, PayPal Buyer Protection, or requesting a chargeback from their payment provider) a buyer is required to use only that process to resolve the transaction issue.

from here  -

http://pages.ebay.com.au/help/policies/money-back-guarantee.html#relationship