As far as this case goes I don't think the seller is legit.
I wouldn't be so trusting in the information a stranger is giving me. Forget about Apple's servers being screwy how about this. The seller could very well be a liar and a thief. People do it all the time.
There are thousands of stories of this happening with a iPhone. There's nothing flawed in the activation lock process. If you own the device you can remove it from the device.
The seller has been most cooperative in this. I'm meeting him tomorrow morning to attempt to resolve...