People mount 315s on 9" wheels all the time, so it's not shocking someone would put them on 8" wheels. The tires in those pictures are bulging off the rims like 10lbs of bologna stuffed in a 5lb bag. If those were 315s on a 10" wide wheel, they wouldn't look anything like that....no way in hell 315's would fit on an 8
This is a matter of common courtesy. Whether intentional or not, the product was misrepresented and the buyer didn't get what he paid for. If I was the seller, I'd refund the money to the buyer and pay for him to ship the wheels back to me.
Don't consider a deal closed until the buyer has received the goods you're selling AND he is satisfied. :idea: