Excessive amount paid for loan closure to MAGMA Fincorp Ltd but they are not returning excessive amount back to me

Hi!

Myself Surgyan Singh took a mortgage loan from Ge Money-Jaipur Branch. Magma Fincorp Ltd takeover the Ge Money home loan business. So my account is automatically shifted in Magma Fincorp Ltd.
I had closed my loan on 6th December 2013. I paid approx Rs. 8000/- in excess during loan closure.
They told me that we will returned excessive amount within 30 days(as per our company policy).

After 30 days, i called on their customer care No. 18001033375. They told me that it is still under process. Today (21/1/2014) again i called on the same no. and i got the same reply.

Are they really following their standard operating time Limit (30 Days)?

Don’t you think they should also pay me same interest rate (18.70%) which i had paid for loan repayment.

Kindly help me out.

Thanks & Regards
Surgyan Singh
08527371315