Keeping my deposit hostage

I rented a car on 24 April and returned on 3 May. I was told my deposit would be paid in within 7 working days. I have emailed and phoned numerous times and still have not received my deposit. When I phoned I was put in a cue. Usually I am placed at 5th, when I get to 1st place in cue, I am placed at 5th again. Why???? I have emailed *** , *** and *** . Chandre kept saying I should email the other two. I have not received a reply from either of them. I have also logged complaints on their website. No reply. Nothing. How do I get these people to pay back my deposit?????