Can Fin Homes — amount partial adjusted

Address:

Gautam Buddh Nagar, Uttar Pradesh, 201318

I have a home loan from can fin homes nehru place, new delhi branch from 2009.

I am paying rs. 15000 as emi from disbursal of load in sep'2009. This was used to be adjusted in interest first and rest amount in principal balance. Last month apr'19 again, i paid rs.15000 as usual but only rs. 5, 723.00 adjusted and rest amount parked. When i contacted branch, they say this is new rule from nhb.
My question is why this amount parked and why should i pay interest on the amount which i already paid. No any update from the bank what will happen of the excess amount what i have paid to bank.
I mailed to "grievance. [protected]@canfinhomes.com" and also raised in grievance portal but still no any response.