HOLDING DEPOSITS REFUND

I rented a car with thrifty and I was charged a R15000 holding deposit, on the 28th of February I had a brakedown with their car and I called them to come and collect their car, they sent a towing truck from East London to collect their car , I asked them about a caretersy car as my rental was not finished, they told me to pay R30000, which I refused and went to rent a car from another rental company, the rental company who assisted me refunded my holding deposit in two days after returning their car, but still nothing from Thrifty they don't even respond to my emails, I made several calls they told me about 14 days, it's more than 14 working days now but still no refund and no response from my emails