PSA: Beware of using Viator (owned by TripAdvisor). You make the call but sharing as FYI. 1-One of their vendors (sub-contractors) tried unsuccessfully to scam me (and I'm told from hotels in Hawaii many other people but can't verify that) by claiming they would not honor a ticket for my daughter and wanted me to purchase another child's ticket. No way. So went with another vendor and it was a great experience even a few $ for the Viator purchase. 2-Assuming that Viator didn't know of actions by their vendor, I contacted them. Horrible customer service. No replies. Then talking with (I think) offshore customer service that didn't understand the issue and refused to elevate. When I contacted the most senior Viator management directly, mostly no replies but one person promised a reply. But of course, no reply. 3-I contacted their parent company TripAdvisor's CEO Matt Goldberg. I immediately received an email from someone else. But after claiming to be interested in dealing with the issue, they did not do anything and keep misunderstanding the issue, despite being regularly corrected on the facts. Anyway - I am sharing just as a PSA. I will never use them and would recommend others to have the "buyer beware".