excess fees charge

I was taken admission in July 2012 from ksou university for a course of mba in hr for 2 years through imi institute in Mumbai. but they charge extra fee from me, actual fees per semester is 13000/- n they taken from me 17500/-per semester, I was paid up to 3 semester n 2000/- extra for exam fee per sem, but when I ask about this they said they are apply service charge from student becoze they provide a course of university for a student, then I ask a give me break up of servie apply for a student, n they denie they said they are a collebratel of ksou n school guru eduserve pvt ltd, n they have right to take amount from student whatever they want, n that tym I said to him just refund my all the fee I dont want continue my study , an after that they ignore me my calls my mails they also said do whatever u want. pls do something sir