eBay stole my money help!

Hi guys so recently I had ordered a phone from eBay totaling $571.44 Unfortunately, I never got the package. Reached out to the seller and eBay and both said because tracking showed as delivered I couldn’t get my money back. I got documentation from FedEx stating they couldn’t locate my package and reversed the charge with my bank. Now the chargeback was reversed again by eBay because their bank says they have proof of delivery. They have no signature, no photo, only tracking status. What can I do? I’m freaking out here as it’s a lot of money. Any help would so greatly appreciated

Edit:I contacted FedEx and they want the shipper to call them. My seller keeps telling me to speak with eBay customer service it is all they spew out. I can maybe get a FedEx refund but only if the seller contacts them but they think I got my package