Booking funds not released on time

I rented a car on the 29th of September 2023.I swiped my card at the Down town dealership (branch)there was an error which separated the holding funds R8245.82. &R15200. I returned the car on 02/10/2023 signed the agreement and the rental difference was returned for the R8245.82. I checked the balance and the R15200 was not released. I’ve been calling trying to resolve the matter but I’m not winning. I’ve made calls to their customer service department and complaints but I’m not winning my funds are still on hold. I’m really disappointed with the way I’m being treated. I feel helpless