I'm currently in Amsterdam, a week ago I purchased a skip the line Van Gogh museum with a Hop On Hop Off canal boat tour. I went to exchange my voucher for a ticket and was informed that there were no more time slots for the day of purchase, looking through my voucher it was NOT noted anywhere that I needed a specific time for entry. Apparently that is standard around Amsterdam. When I informed Viator I was met with sorry you were a no show you are unable to get a refund. I explained I was not a no show that they sold me a voucher that I could not use and was told I should have bought the insurance with still no refund. Worst customer service I've ever experienced and suggest looking at other sights so you don't get sucked into a trap as I did.