What can I do regarding a school and employer mistake which results to my working for 7 months and not getting any internship hours?

I am student in graduate school. I am getting my PhD in psychology. I finished almost all my courses and just need to finish 3000 hours as an intern to be able to graduate and take the board exam. I started internship at the clinic and both my school and the clinic agreed and signed the contract that this is a right site and I can start getting my hours. After 7 months and spending 800 hours, the clinic found out that my school was not part of their agreement with the Board to get my hours and I don't get any hours. This was a non-paid internship and I was working full time for 7 months. Now I am sitting home with no credit as far as hours and it will keep me at least one year from graduation and starting my career in future. My school told me that the clinic is responsible because they should know if the intern is right for their site and the clinic told me that my school should know where to send their student. I don't know if I file a law suit against my school it will put my graduation and licensing process in danger or not. I am very desperate and need help.