Ok, you gave it a second chance, which was very generous of you considering your first experience. I would have led a revolt half way through the first class.
Since she's trying to do these classes herself, and had no one watching her shop during the first class, she's probably trying to keep her head above water by fulfilling the roll of shop keeper and teacher at the same time, but taking your money and giving you partial time and hit and miss instruction is a crime!!
I'd ask for my money back. I'd tell her I had the time for when the class was originally scheduled and I was there, unfortunately I'm unable to make your rescheduled class time so please refund my money. If she refuses and you end up taking the rescheduled class and you get the same partial time and hit and miss instruction, I would be noisy about it during the class and I bet others would be as well.