With 8,800+ unread emails, my guess is that he is a scam artist and those are bounced back emails... I'm like you, I baby everything I own, and I would KNOW if my stuff had a scratch on it... IMHO, I think he's trying to scam you... How do you know the picture he's sending you is even the same phone you sent him? Make him send you a screen shot of the IMEI and the scratch!
Enough with the emails thing...As soon as I updated to iOS 7, my email showed the same thing. I had to " select all" and delete. It's a BUG, not evidence of a scammer.
Once you get YOUR phone back, call eBay and tell them that you didn't receive item back in original condition. I had someone send me back my item damaged and eBay refunded me after paypal sent me negative. They also made a record of what happened.
Matt