How do i report a college for improper money distribution?

Okay. i am a sopre in college. Now mind you, i have a full scholarship that requires that my fafsa goes toward my bill, but other than that everything except like two hundred dollars is paid for. Last year, i received a refund check for the amount that was left over on my bill. This year when i got an increase in the amount of grants i received, i no longer have any refund and for some reason they used my grant money to go towards my bill. when i voiced my concerns, they said that it was correct and im mistaken. But my feelings are that if i am on a full scholarship shouldn't my scholarship pay for EVERYTHING! Why are they using my grants and things to pay for my bill!! I know that they must be keeping the money for themselves or something.