My ticket to Fondation Louis Vuitton in Paris did not work. The kind lady at the entry chuckled at me...She had seen this before. She helped me buy another ticket so the day was saved, however Viator would not refund my ticket. Really? The cost of the ticket was not much and a single review like this could sway buyers...Short sided and unhelpful. I see they have a 1.1 out of 5 review already so I guess their business model is to NEVER REFUND. NO more trip advisor for me.