I would argue that it isn't a straight customer relationship, because it is also falls to the professor to hold you accountable for that information. You are paying for the credit as much as the lessons. The professor isn't just hired to serve the students, they are hired to create and implement a curriculum that will allow the school to give those credits. You then pay the school for that credit. Hopefully those credits are then useful to you in pursuit of a career or financial growth. That's one reason why tenure exists. In most service jobs, keeping the customer happy is a top priority. In education, it is secondary.
Realistically if you are just in school for personal growth, you should have the financial flexibility to do so, because you are a hobbyist at that point.