Too bad they wasted your time: You can always ask for an explanation. As a Diving Instructor myself, I honestly don’t know how anybody could "miss" a rescue class, especially, a rescue class. After all, Rescue Classes are based on the idea of what do you do when things "happen." Have a rescue plan ready. I would feel very nervous about learning from a Rescue Diver Trainer who didn’t have a plan for when he or she couldn’t even show up, lol! And you didn’t get a call? Or a message in a bottle? They didn’t have a dolphin come over and knock on your door with its flipper to tell you? Teaching rescue classes are really fun, so what happened?