Ask your financial-aid administrator to issue a dependency override. Overrides are granted only in extreme cases and generally only when it's impossible to contact your parents or you would be put in physical danger by contacting them. Only 2 percent of students are granted a dependency override per year (see Reference 1).
Petition a family or civil court in your area to remove your parents' parental rights on the grounds of abandonment. Abandonment is one of the few reasons that can lead to a dependency override. Testify that your parents have had no communication with you nor have provided you with any financial support for at least one year. You can strengthen your case by bringing in family witnesses to testify on your behalf, such as a sibling, aunt, uncle or grandparent. You can opt to hire an attorney if you do not wish to represent yourself.
Get married. If you have a significant other and are thinking of tying the knot anyway, marriage is the only other way to remove your parents from the equation of student aid before reaching age 24. You will be considered independent only if you apply for federal student aid after you are married.