While it says iPhone 6, it also says "latest model." Maybe people thought you had a 6s somehow? Either way, it's 98% sure to be a scam, and the winner will probably try to retract.
I'm so done with eBay, and the bullsh*t that accompanies selling something expensive online. The iPhone forever plan has saved me from the inevitable late-summer headache of trying to sell a phone to some foreigner who doesn't comprehend online bidding. I've had people jack up the price last second, only to cancel their winning bid TWICE.
Just today, I got an email from the winner of my iPhone 6 that they received 6 days ago stating the iPhone is iCloud locked, and how they're going to report me for selling a stolen phone. I listed it with 7 pictures, and two of them were the receipt, and a screenshot of the logged out iCloud screen. I called apple just to double check, and they told me the phone was recently logged into with a SIM card from Hong Kong, and re-locked with iCloud. This person is trying to scam me I to giving a refund after they probably just needed it for a quick trip overseas. So done with eBay.
Sent from my iPhone 6+