Will i really obtain the schegen visa from the german embassy so soon?

I am a kenyan citizen by birth and I recently applied for a schegen visa at the german embassy nairobi.after 2 weeks of time I received a letter from the embassy denying me the visa.my traveling purpose was to study the dutch language at Hartnackschule in berlin.after observing the letter I corrected my mistakes as indicated.yet the embassy remained with some my original documents(certificates of education) holding me back not to be able to apply again for the visa.when I ask for my documents I do not get them.I was to join the dutch school in berlin on 29-june-2011.till now am stranded.I need some help to be able to obtain the visa so that I can join the school by the indicated date.plz help because I have already paid the school fees.