Reliance Power — Dealy in Refund- HNI investor-Interest charged higher by Financer

Dear Sir

I has applied for the RPL issue taking a funding from one of the top financial institutions.
I was conveyed an ineterst rate of 19% for 15 days and it was very categorical that the interest will be charged for 15 days only.
However, refund was received late as per the financer and as the refund amount was received by that company, they deducted an additional amount of RS. 45000.00 around saying that they received the refund 3 days late.
1. Who is responsible for the interest on delayed refund. The financer now says that it is the industry practice to charge the higher interest from the investor.
2. It was very well communicated that interest will be charged for 15 days @19%. A mail to this effect is also available but its language is dubious. The excel sheet attatched shows all calculations for 15 days ineterest etc.

Please guide in the matter.
Thanks

Dinesh