Frankfinn Institute Of Air Hostess Training — Refund of extra 9000 paid mistakenly

While my admission in frankfinn institute kothrud pune my father sent total number of 11 check of amount 9000 each for further installments.
During 1st month of my training my COM mam came to me and said due to some reason we're unable to post the 1st installment so kindly pay via student portal
So I paid the 1st installment through my bank account in this case at the end of the session there must be 1extra check gets left and when I asked them for the same they said there's no extra check every check has been posted on the bank account. So you see there extra amount that has been paid and I'm asking for refund so they're no doing the further procedure.