Delhi University — double payment of fee online

I pay my college fee online on 31/08/2017. But i don’t receive any confirmation. Then i again make payment of my fee on 7/09/2017.
I also complained this to my bank also but they said that transaction is sucessfull.
I still don’t get my refund.
Name - vishwajeet singh
B.com (P)
Cbcs
Roll no. [protected]
College - sri aurobindo college (Eve)
Reference id - [protected]
Amout paid - rs.5045.60