I was lucky enough to find a really good class, and I remember the instructor mentioning that she wouldn't do teach with Hancock's anymore because they aren't prompt about paying the instructors. I can't help but think it demotivates instructors to do a good job, and that it means the instructors they get aren't necessarily good or qualified.
Also sorry to hear about your experience and yes, ask for the money back if only to make sure they get the feedback.