You may not have recourse here. The only thing you have going for you here is that you did return the phone. If you have delivery confirmation as proof that the phone was received by the seller, you can attempt a chargeback through your credit card company. If you used PayPal funds, or a debit card, well, it's not looking good.
Indeed you have exhausted your time limit through eBay and PayPal. You may be able to file a suit against the seller in small claims court, however you really have to ask yourself if it is worth it.
Post a negative feedback if it's not too late. A 100% seller with a top rating wont do that. Never buy from a new seller or from China. Ebay cant help you because it is more than 45 days from the auction date. Did you check your tracking number to see if he received the phone back? If he lives nearby take him to Small Claims court.
First thing is first, are you able to contact your bank to ask for a charge back?
Did this seller have good feedback?
You're in quite a little situation. If you have the details of your seller, report him to your local police for theft. Tell them to write a police report and tell your seller you have done so. See what they will do from there.
eBay have rules set in place for refunds and problems within a certain time period. Always be aware of this. If you go past this time, then they won't help you at all. It's apart of their guidelines and all buyers and sellers need to know this. Most sellers on eBay are certainly honest, but you do come across some dodgy buyers on bad days.
In future, for electronics or high cost goods, you should purchase them in person or buy them from a well known bricks and mortar store. Therefore if worse comes to worse, you can always take it in store to get help.
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