Kaplan University Rip Off upcoming graduates Online College, Florida

I am currently an online student at Kaplan University. I only have one term left to graduate (2 classes) and I was hit with a bill of $1,600. I was not given sufficient time to find out the details because I was told only a couple of months before my completion. I had a friend that went through the exact thing and could not finish. I have been a student since September of 2009 and I have invested too much to have my education in jeopardy because of money. My only income is SSI which is why I was eligible for financial assistance plus loans. They have been calling me off the hook because they expected an $800 payment on August 1st. I don't even get enough money to pay my bills and not to mention food for me and my son. Why do they do this to everyone right before graduation? I need help! I want to graduate. Going for my Bachelors in Science of Criminal Justice. What should I do, or do I just throw 3 yrs of college down the drain? Someone has to put a stop to this or there will be many in poverty that already suffer financial burdens. Thanks!