Relief to frustration - deposit not returned

It was a relief when Thifty had cars available when my husband and I landed in Cape Town in January, as several other car rental places at the airport turned us away. That relief has turned to frustration. It has now been 17 days since the car was returned in pristine condition on 31 January, and my R3500 deposit has yet to be returned. On 5 Feb I went to their office in the airport and asked about it, and they said it has been released and can take 7 to 10 days to reflect. Nothing appeared after 14 days so on Tuesday 14 February I phoned and again, they made promises about followups. I haven't got a call, or an email, or my money. What's going on?? Why should I have to chase for money they took within seconds?

Reservation No. ***25