Green motion car rental are ******

We rented a car from Green motion Johannesburg and took the car back on 10 April 2023. They had to give us back a deposit of R11000. 00 within 3 weeks and they didn't. It's been almost 3 months now and we're still struggling. When we call them, they only say they'll get back to us every time. Called again 3 times today and still no response. They are ******.