Consumer Redressal

hi my name is bhinder singh i booked a self drive car from delhiairport from carzonerent booking id 4647521. car picked up on 25/10/2013 and drop off 18/11/2013. on pick up car zone rent took a bond of rs50000 from my bank card. which was to be refunded on return of the car. i have been chasing the company from last 8 months and they saying that money has been refunded but no proof was provided by the company. i have told the company that i will be putting a case against them and refund of 50000 with an interest of 21% but the reply from car zone rent was that they are standing their ground. so i want to file a case against car zone rent for a refund of my money with interest of 21% i have all email communications with company accounts department. regards bhinder singh