Make sure you have amended all of your addresses - you have to change your address five separate times.
Updating one address doe not change the rest.
Then, contact the buyer and ask them if they will return the item to you at your correct address.
You will need to provide payment for postage or a label.
There is nothing you can do through Ebay.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)