I would believe what I read in Ebay's terms and conditions:
When you challenge the payment dispute, the final outcome will be decided by the buyer’s payment institution. The payment dispute could take up to 90 days or more to be resolved, depending on the payment method or card provider. eBay may hold the funds from payout up to 90 days from when the dispute arises.
What reason did the buyer have for the chargeback? Was it 'did not recognize the transaction'?
Do you have evidence that the item was delivered to the address used to buy the item?
"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)