EBay had wrong return address

[dude_1973]

I sold an item and the seller decided to return it but was sent to an address I don’t not know. I looked at my account and somehow it was changed from my address to a strange address I had never heard of over 100 miles away. It sounds like I got hacked. EBay says there is nothing they could do and got smart with me and said there was no way I did not know about the address the item was returned to. Any suggestions on what I can do? 

[myescape]

did you report your account as hacked and change your password?

 http://pages.ebay.com/help/account/securing-account.html 

You will refunding when tracking shows item delivered and ebay will not get your money back