First thing first, file ITR within prescribed time.
RTI is not a remedy. Through RTI you can get only the material form of record that is in control and custody of the Public Authority. Even without this RTI, you can get your statement on demand as a consumer/depositor from the Bank.
Issue a Notice under CP Act to the concerned Bank, alleging deficiency of service on part of the Bank, claiming for reiumbursement of such interest, expenses, compensation of Rs.10,000/- for harassment.. If they fail to reverse the interest file complaint before District Consumer Forum.
The Limitation period for filing consumer complaint is 2 years from the date of cause of action. The complaint filing is just formal and requires no expertise, and any common man with basic education can file such complaint. The maximum costs may not amount to more than Rs.500/-
Banking Ombudsman is also the other way. You can approach both Ombudsman and Consumer Forum and for filing such complaints, issue of notice is mandatory. Once the Bank replies, depending on the version you can proceed further.