Call the Central Service Call at extension 11 or report the damage electronically with a ticket to Division 3 - Facilities Management of Technische Universität Braunschweig. Ticket system
Responsible for renovation and conversion is Department 35 - Building Construction and Maintenance
Please send inquiries directly to the head of the department by email. abt35(at)tu-braunschweig.de
I can find the appropriate form under Forms and downloads
The areas of responsibility of the janitors and their contact details can be found under Service
For an explanation of how buildings (and rooms) are labeled, see Buildings and Rooms