Buyer returned empty phone box

[cheapdeals2k16]

I sold fold 5 on eBay. Buyer wanted it for his kid and offered a little on low side but I ended up selling it to him to make his kid happy. Anyways, after more than a month he said it's not the same or "item not as described and sent me picture of a different IMEI" I let EBay know right away that it's not my item. However, eBay asked me to accept return and once it arrives let eBay know. I did that. I sent him prepaid return label and he shipped it out. Once received and opened the box it was just an empty phone box along with trash/amazon boxes. I let eBay know that as well along with pictures. Case was opened and eBay still refunded the buyer fill amount of $1100 and took money from me. I cannot afford to lose that much as I have rent to pay. What do I do? 

[disneyshopper]

ebay's Money Back Guarantee expires 30 days after receipt of the item.  You stated that it was more than a month before the buyer contacted you.  You should have declined the return because it was past the 30 days from receipt.

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