Avis bad bad service

On the 6th September I picked up a rented Car from Avis King Shaka. Was asked to produce my credit card for some deposit. I didn’t have the physical card on me and was told they don’t take virtual cards. I proceeded to use my business cheque card. On the 8th September I returned the car and got an invoice for less than R100 to refuel the car. Avis debited my account on the 11th September for the full R3500 amount that was meant to be just a hold until the car was returned. I have called Avis and emailed their branch manager at King Shaka as well as their customer care manager on Wednesday 18th September. To date I have had no response to my email and my money is still not refunded.