Federal pell grant help!!!?

I am a junior at ball state university. I was called to active duty for a deployment that i am currently serving on, before the end of the spring 2009 semester. i am now receiving reclamation letters stating that i owe the grant money back. This was obviously out of my hands and i don't feel as though i am liable for this supposed debt. I need an official statute that i can cite to help my case. Thanks in advance to all of those that help.