Do you back your Paypal account with a credit card?
Go to the 1-800 customer service number on the back of the card and phone about a chargeback.
The company may not have received the phones back. Are you referring to proof of shipping or proof of receipt? EBay and PP want proof of delivery. Some cards allow proof of shipping. Not all.
Return shipping is a low priority for the postal system. It can be very slow.
Even so, 180 days is six months. You could have filed an "Item Not Recieved" dispute with eBay after 30 days. Water under the bridge.