Your question is hard to answerwithout all of the facts.
If an item was paid for and delivered on your account it must have been ordered on your account. You need to check you recent purchase history in your "My eBay" pages.
If your account had been hacked, I would have expected the hacker to change the delivery address. Are you sure that you didn't order it yourself, and forgot, or could a member of your household have used your account without permission? Both of these happen!
It isn't clear whether the iem was paid for direct from your bank account, or from a credit or debit card associated with the account. The latter would give you more protection, but unless the seller is a business seller and required to accepts returns it's far from certain that you would qualify for a chargeback because they won't accept a return that was ordered on your account.
