Interest rate

You may ask the head office of the bank the base rate from June 2013 till now to ascertain your doubt was correct. I don't think a bank will cheat you alone telling the base rate was increased. Banks have many other ways to cheat without your direct knowledge. Banks have discretion to fix base rate on a particular day applicable to all their branches, but according to the risk perception addition of some percentage over the base rate, which may vary for different accounts. If you are not satisfied with the said bank, you may switch over to another bank of your choice, if they take over your a/c.

You may obtain the base rate from time to time in the bank's website.If not seek it under RTI Act and have it checked with your loan account statement. Should there be any variation,take up with the branch  in writing and in case of no response ,refer to the controlling office.Again if no response, you have option  to refer to the Banking ombudsman and RBI too till your grievance is redressed to your satisfaction.

I would tell you that first you find out in deatil through RTI if the Base RAte charged to you was correct or not. In 1  month you will get the reply.

Further, you can write to the banking Ombudsman with this complaint and you wil be heard on this. Before this step you should write to the GM etc of your bank, get an answer to this.