Reduced Pell Grant 3 months after bill was paid

<p>I was all paid up on my summer class at NYU where I had been enrolled half-time at 6 credits. This morning I get an e-mail saying my financial aid had been reduced and I now owe a balance on my bursar account. They quartered the amount I was originally receiving based on my credit hours, which originally stated it was based on my anticipated enrollment of six credits so nothing seemed amiss. My EFC is 0 and I passed up on taking the federal loan that was offered to me at the time. They are saying that since the semester is over I can no longer take the federal loan I was offered and I should take out a private loan to cover the cost. Is there anything else I can do to fight them on this? Are universities allowed to reduce Pell Grants 3 months after the original bill was due? Any advice is appreciated. </p>