Ebay Buyer paid for item but won't go pick it up?

A buyer on ebay bidded on my iPhone 4S for $460, and the next the I shipped the phone after I got paypal confirmation that he paid. I also shipped with signature confirmation but the problem here is after the 1st attempted delivery by USPS, the phone will sit in the post office for 15 days before being mailed back to me. This is my only phone, I was hoping to use the money for this phone to get another. AT the moment, I'm phoneless. I sent the buyer two emails, one stating the tracking number and the second to tell him that the phone is at USPS, waiting for him to go get it. He has yet to reply. I called him today, some lady picked up and said he was going to go get it today.
it's 3:15. The post office is closed and he never went.

I paid ebay and paypal fees plus shipping. What do I do? :/
Those fees are coming out of my pocket.

Added (1). Paypal withholds the payment for 21 days…
the buyer can file a item not received and get every penny back

Why are you concerned if you received payment already? If the phone is returned back to you, the buyer will have to pay you again for shipping to them. They are also not allowed to dispute not receiving it, because ebay terms and conditions require them to complete the purchase unless you have a refund policy on the item. If you have a refund policy on the item, then you need to consider it.

No, they buyer can't do what you suggest. You shipped the phone, and you have the tracking number. You're either going to end up with the money, or with the phone if he fails to pick it up. Yes, PayPal withholds payments, and they do that for EVERYONE. When you sell on eBay, you should expect monetary delays.