In such a situation, it is important to keep in mind that the relationship between the student and the faculty member is not akin to a “consumer-provider” relationship, even if the student is paying fees for her or his education. Rather, the relationship is one of mentor-mentee, two parties engaged together in creating and transmitting knowledge. It is therefore not appropriate for the student to demand “services” of certain “quality” from the faculty member. At the same time, however, the faculty member’s seniority does not entitle her/him to dismiss negative feedback, especially if such negative feedback indicates the student is not growing under the mentorship of the professor.
In practical terms, this means that a student should always approach a faculty member with respect but should not be afraid to politely raise difficult issues. Fear of repercussions has no place in a mentor-mentee relationship, at the root of which should be honesty and mutual respect. A good professor will recognise and reward constructive feedback and will not punish the student for it. Indeed, a student’s ability to generate constructive feedback and relay it to the professor in a respectful manner is an indication that the relationship is working and the student is growing. If the professor is not open to such feedback, the situation can often become more complex, and solutions might require involving third parties who can mediate the situation. Doing this is preferable to the student bottling up negative emotions inside, as these will often not go away but make things even more difficult down the line!
You may ask (as was done in the comments to this post) what a group of students can do if they are unhappy with a professor or a course. This is a good question. In my experience, many students do not feel comfortable with confrontation. Let’s face it — most universities, however egalitarian they might appear, are hierarchical organisations in which challenging someone “above” us can be daunting. In my capacity as chair of a student representation group, I’ve heard students talk about their career prospects being compromised if they alienated a particular professor, about not getting the coveted glowing reference they believe they need to secure an academic job. In this way, students can become socialised into the hierarchical culture of academic institutions and, often unknowingly, keep reproducing the same problem in their later careers as professors (if they choose this path). There are no easy solutions to this, culture change is slow and difficult, and not everyone is a risk-taker.
My advice would be for students to first try to go through any student representation mechanisms existing at their institution (student reps, unions, academic societies representing students’ interests); student reps are often experienced and trained to handle such issues.
If effective representation structures do not exist or are too slow or ineffective, my second choice would be talking to the professor directly, if one or several students are willing to do so.
If not, my third choice would be approaching the head of the program or the head of the department. This can backfire however, many academic departments have their internal politics due to which the head of the department, even if in agreement with the students, may not be able or willing to champion their cause, and it can cause resentment in the concerned faculty member — so I would always consider talking to the professor directly, if possible, rather than to their superior.
If none of this works or is too slow (as is often the case with universities, which is unfortunate, because student-related issues can be very time-sensitive), I would consider either launching a formal complaint with the university (if students are willing to come forward and submit their non-anonymous accounts), and as a final option writing an article in a student publication. This last option is, in my opinion, a perfectly legitimate option, as publicly (and anonymously) exposing problems makes perfect sense in an environment where there is power imbalance. The reason I am suggesting it as the last option is that while it can be very effective, it can also create a lot of negative by-products in the form of resentment, compromised interpersonal relationships, and undermining a culture of trust, and these could, in turn, fuel other problems. There are certainly many cases when this approach was successful though, and I would not discourage anyone who is set on pursuing this course of action.