I've booked two tours in Brazil and few hours after that I received an email from Viator stating that both my tours were canceled because they suspected credit card fraud and also stated to check with my bank. I called their customer service for some kind of explanation but none was given even so they put a charge on my credit card. I called my bank and there was nothing wrong with my card as I suspected. They said I will get a refund in 5 to 7 days, but as I read the other comments I might have to open a dispute with my bank. Stay away from Viator - they can ruin your vacantion!