I am self-taught and only took one class back in the early 1990s as a college extension fun night class. That was back before rotary cutters etc. The teacher was great. But I have never taken another class because I tend to be a personality that likes to self-learn just about anything. I didn't take the study classes for a work certification but passed them all, etc.
So I say if you aren't enjoying it, you stop attending. It's up to you if you think you have a case to get your money back. If your techniques work for you, then they do! There is no "right" or "only" way to do just about anything in the quilting world.....