Refund deposit

Discovery Insure hired a car on my behalf as a courtesy car.The car was delivered to me on the 20/07/2015 and the gentleman who brought the car asked for my bank details as I was paying cash and I gave them to him.The car was collected on the 18/08/2015 and there were no damages and the petrol tank was full.He asked me again for my details and I gave to him again.I then received a voice message to call them to give the details and I did that. I then wrote them email to remind them that I'm still waiting for my deposit as they promised that I will be given my deposit within 7 working days and they responded that they will pay back all my deposit of R1200 by 20/10/15 and that date went past. I then wrote them another email that I'm still waiting for my money and I never got any respond.May I ask for your intervention ion this issue