I had booked this several weeks ahead, and provided a credit card that I later canceled because of fraud on the account. I didn't remember that the charge for the cooking class had not put through already, and the first time I knew there was a problem was the day before class was scheduled when I got an email saying the reservation was cancelled. I quickly called the local tour operator to provide a different card to pay for the class and was told it was too late, that I had cancelled the class myself. Then they offered an alternate explanation: that my sister (whose name they had because Viator asked for it when I made the booking) had made a separate reservation (she had not) and that she had canceled the reservation (she had no communication with them at all). Given my quick response to their email, and the two different reasons they gave for the cancellation, I was suspicious when they told me I couldn't rebook because the class was full. My guess is they got a bigger group booking their space and could make more money off them, so they canceled us. I called Viator, and they responded promptly but were unable to solve the problem. We were not able to attend the cooking class, but weren't out any money.
Given some other complaints on TA about this local tour I thought I would alert people to the problem we had with it.