wrong interest charged in my loan account

Location/place: mishra colony, rajpal chock, hariom bhawan, chhindwara, 480001

Name of company/service: union bank of india

DEAR SIR
I WAS TOOK LOAN FROM UNION BANK OF INDIA AT CHHINDWARA BRANCH OF RS 500000/- ON 8% FIX RATE INTEREST. BUT AFTER ONE YEAR THEY CONVERTED MY LOAN ACCOUNT FROM FIX INTEREST RATE TO FLOATING INTEREST RATE WIHTOUT GIVEN ANY INFORMATION & TAKEN APPROVAL FROM ME. THAT IS TOTAL AGAINST AREEMENT WHICH IS CREATED BETWEEN ME & BANK AT THE TIME OF LOAN SECTION. AS PER BRANCH MANAGER THESE CHANGES DONE FROM HEAD OFFICE. I WAS SENDING APPLICATION TO HEAD OFFICE BUT DON’T GET ANY REPLY FROM THEM. ALSO BM SAID AT THE TIME OF GETTING LOAN GIVEN SUBSIDY ON LOAN 1% THAT WAS NOT CREDITED BY THEM IN MY ACCOUNT.
SIR PLEASE TAKE PROPER ACTION WHICH IS SUITABLE
THANKS TO GIVEN YOUR PRECIOUS TIME