Car returned Feb 13, 2015 full tank no refund

I HAVE been trying to call AVIS without luck and have to resort to this form of complaint.<br> <br> <br> I collected the car Monday February 9 which was hired via Discovery Insure, I paid R1,200 deposit which I was promised to have it returned back in full when I return the car with full tank at Cape Town International Airport.<br> <br> I did everything as required, but I now have to struggle to get my deposit returned, am very disappointed with Avis.<br> <br>