You can lodge your complaints about the use of your personal data with the data protection officer. 

If you lodge a complaint with the data protection officer, please make sure that you supply all information that can be of importance in dealing with your complaint; for instance, copies of the correspondence between you and DUO. 

Dienst Uitvoering Onderwijs 
t.a.v. data protection officer 
Postbus 30155 
9700 LG Groningen