Pathetic service Avis Bloemfontein

My Husband rented and returned a car from Avis in Aug using my Credit card. I have not received my deposit to date. Avis advised that they refunded us, which did not happen. We sent them a bank statement which indicated that there was no funds released from their side. After we sent them the proof that they did not pay us back, they advised that there was a confusion. We took a car 2 days after we were called to come change the car as the 1 we had was due for service. So the transaction showed as if we were refunded when they gave us the 2nd car. The statement we sent shows that the funds were paid over to AVIS. They also admitted that indeed the funds shows on their side and they promised to refund us. It's now the 15th of Oct and we are still waiting for a refund. Our insurance also sent them a request for a refund. All they do is keep promising that the funds will be paid within 48hrs which never happens. Now, AVIS Bloemfontein does not even respond to the whatsapp messages as they've been communicating with us on WhatsApp. We are now being ignored completely. And we also tired of calling them, following up only to get a promise that's NEVER KEPT! VERY UNHAPPY WITHVTHEIR SERVICE. Because when you are the 1 who owes or have to pay them, they never waste time to threaten you and they make sure that they collect the amount owed, but we struggle to get our refunds!!!