I think before filing a application under
RTI Act-2005 you should write a request letter to the officer concerned with your ward / range etc informing/requesting him for the refund .Please make sure that almost 98% refunds are delayed due to the fault of assesse because they did not furnish complete bank details for the refund. Now the government has made account number/details of assesse mandatory for the refund.Provide your complete details in your request letter.
In case you did't receive any reply from the concerned officer with in statutory period only then it is advisable to file an application under
RTI Act-2005.