Student Visa (F1, F2, M1, M2)

I am on F1 visa and I had a problem where my teacher drop me from the class without even telling me. Unable to add another class, I figure there would not be any problem because I was going to pay for this class anyways. Turns out I fell out of status and my student coordinator came to know about too late. She ask me to apply for I-20 reinstatement and it is been a year since we summited that application. Does anybody know how long does it actually take to get a F1 reinstatement?