I have had this problem before because I failed some of the courses I was enrolled in. All you have to do (usually) is go to the schools website and there should be a financial aid appeal form to print out. I had to meet with an advisor and they had to fill out part of the form and then I had to fill out the rest stating why I had trouble the semesters I did. Then you turn it in and wait for a response from the school (usually by mail). Make sure you include the documentation to prove there was a reason you were having problems (medical papers, note from the doctor, etc.). Good Luck!