Hi,
we are having 15+ years experience in working with asterisk based solutions, either its vicidial, freepbx, astpp or any other software.. we have a our customized versions of call center, multi purpose, billing system.
Recently we worked on a bit similar project for a girls hostel having 4000+ students, the students can recharge there number from billing department and call call the numbers assigned to them.
lets chat and we can show you our customized systems.
thank you.