You can file a complaint if you feel that you have been treated inappropriately by a lecturer or university employee, or if you are dissatisfied with the quality of facilities on campus. You can also file a complaint if you are dissatisfied with the state of affairs at your faculty or your study program. Note: the complaint must relate to a behavior, and can not be directed against a general regulation.
For more information, see the general website of Radboud University.
More information about how to complain, can be found here.