Failure to Pay my Refund

I am actually disgusted, my car went into Nissan springs for 6+ weeks due to a fault it had , 3 weeks later they hired me a courtesy car from thrifty rentals which I had to pay an upfront fee or R600 and upon them collecting the car back I was supposed to get the R600 - 3 months later and I’m still waiting for my Refund - this all happened during April and May 2022. They keep on saying they will pay me back but nothing