Hello Bernard, really sorry to read about your bad experience. Many thanks for sharing this and having the guts to come out and share your painful mishap.
It's doubly scary when the crooks are people who used to be reliable sellers on reliable sites.
Even the reputation part and "buy-the-seller-not-the-watch" rule do not hold any longer this way - because one risks being the first casualty before the word spreads about bad behaviours.
People will only end up buying from those they know personally in the long run unless some (new?) safety mechanism can be found.
Good luck, I hope you'll be able to recover your money some way.
Cheers,
Fabrizio