Cars24 - Refund not received

They deal in second-hand cars. They charge me with a service charge of **** Rs which are refundable they told me at that time. My loan is not approved due to some reason and deal cancelled. They told me that they start my return process. But it's been more than a month. I don't receive any kind of money. Now the cars** representative gives me many phone numbers to talk with but no one answer the phone.