I'm not sure if the 'online status' is neccessarily valid - I suspect I appear permenantly 'online' as I have TZ open on several machines, 24hrs a day.
BUT - I would say that his attitude has changed once the sale was made, and if you are certain that the mark on the lug is missing from the photos advertised - then he has either decided not to list marks on the watch, or the photo is from an earlier time. Either way is a crap attitude.
You've asked for a refund, wait and see what the response (if any) is - but it sounds like an unsatisfactory deal.