gzt: Are you osx? Photos app should display all exif data I would think..

firefuze: I have tried a few EXIF programs and none of them will show a serial number unfortunately. Just a manufacture as the only identifiable information.

The device was NZ new so is unlocked and will work with any of the US networks providing they are not CDMA (which I did state in the listing details)

Reason for selling on eBay is factory unlocked iPhone's like the ones sold here in NZ catch a good premium over the flooded market of carrier locked devices in the US. Also I buy a lot from the US with my PayPal account so selling on eBay and getting paid in USD is quite handy to have.

kingjj:

mattwnz:

kingjj:

mattwnz: You don't think the box has been intercepted by a third party who has removed your phone and put in the damaged one? I am guessing Apple keeps a record of who the original serial belonged to when the phone was first connected to a iTunes account, although whether they will provide that information to authorities is another matter. If is a bit strange that the buyer would be as cooperative as they are with the photos, unless they have done this sort of thing before with another account. If is possible that both. the buyer and seller are the victim.

Possibly, but lets face it, highly unlikely. Courier companies aren't the wild west, they don't leave packages unattended in insecure places. With Courier companies you ether get your package or get nothing, you don't get inbetween.

From the OP's update it seems pretty clear that their is dishonesty and i'd place that (based on info at hand) squarely at the hands of the buyer.

Yeah sounds that way, but I have learnt to always look at both sides just in case. Courier companies can leave things in the wrong place, or just leave stuff on your door stop and signing for it themselves, but the odds of someone switching an iphone in that case, rather than just taking the entire parcel would be very low. 
From what the OP has said, there is the possibility that  the OP is potentially being scammed, possibly by a pro. As they have had a few piece of positive feedback, prior to ordering it, to get a good reputation. What are those previous feedbacks for , and what sort of time were they placed in, and are they a new trader. Can Ebay be contacted by the seller to report a possible scam?

Considering OP said PayPal have put a hold on the funds pending a resolution of the complaint to Ebay I'm gonna hazard a guess and say that the OP will have presented all the information above to Ebay and that Ebay will certainly entertain the possible scam outcome.

The problem I foresee for the OP is PayPal. If Ebay don't come to a resolution than PayPal will (from previous experience) probably revert the payment to the buyer for no other reason than they dislike getting chargebacks and seem to favour the complainant.

I hope the OP wins out here, I can't see any reason to place fault on them and they have kept up there end of the deal.

out of interest, you store you USD on paypal? paypal is also a bank?

Dratsab: Sounds like the evidence you were able to gather did the trick. Great work by you and great advice from the GZ community!