Hi Cambourne,
I had the same problem last year selling a phone on eBay. Some guy named Bob from Florida wanting to send his honourable son working in an embassy in Nigeria a nice new phone for his birthday. Right.
Get onto eBay straight away, you don't need to wait to see if you get payment, we know it's not going to happen, eBay know it too. I was worried I'd have a battle on my hands with trying to file it as unclaimed, but it was dealt with very swiftly. Ebay must get thousands of these requests from disgruntled sellers daily, just say the word 'Nigeria' in a message to their customer support and they'll probably have it filed unclaimed within the same day and automatically cancel the 'buyer's' membership. I managed to resell the phone, but I feel for you, phones are a hassle to sell on there. Best of luck.
:) :)