Groupon: Collective Buying Power

I purchased the groupon for brushes and bottles. I made an reservation for two people, three weeks in advance and the day before my reservation, I received a phone call that the class would not take place because no one else had signed up. I was also told that I could make another, but no guarantee that the class would take place if not enough people signed up. The owner should have rallied people for that class. Three weeks in advance is plenty enough notice. It was for a birthday and I had already gotten a baby sitter. How disappointing!!!