Consumer Redressal

I have taken a HDFC bank personal loan in April 2010. At that time the person who collected the loan from me told me that he was directly from the bank. Later on, I got to know that the person was from the third party and the rate of interest that I was chraged with was significantly higher than what bank was charging at that point of time. Now it has been more than six months me following up with the bank regarding the fraud done with me but the bank is not ready to roll back the interest rate. I have also confirmed with one of the bank\'s branch manager and I have been told that the facts wree misrepresented to me. The bank is threatening me of recovery agents. Please help me out in this case