Help me please!?

I am at a technical college. I am trying to go to a university. I took online summer classes but was withdrawn because I lost internet. I took out a loan to cover book expences and should have gotten a refund. I got one and was told to go sign a paper beccause I got extra. I went and did it. I got the money last week. And a few days later an extra $500. Today I received a email stating I owed them $640. And when I called to ask why they said I received too much and it was their fault. Then I got another call that said I withdrew and had to pay the tuition again. They said I did not have the money to pay it. So why did they give me $2,000 and not take $640 out of it? Soooooo, 640>2,000 now?