Hi Mr. Liran,
Viator denied you a refund is because:
That you has decided to cancel the activity at the time you had already put on the life jacket, then you had a discussion with your wife about it, some of you want to go to do snorkeling but as I explained to you, this is a kayak tour as our description said, and the snorkeling was just part of it (not more that 10 minutes), sorry if you were confussed about you get a refund, the deadline to have it had passed as Viator let you know at the time that you booked it.
When you requested a refund , your reason were WRONG TOUR