AirBnB not following their own Rules and conditions

We were looking for a place to stay in Simbithi Eco Estate as a family to celebrate my ****her's 95th Birthday during January 2020. We found a place through AirBnB hosted by Stuart in Ladlau Drive Simbithi. WE were supposed to arrive on 02 Jan 2020. We duly paid the deposit required R7 500.00 during latter halve of December 2019 under the understanding that the balance would be due on arrival. AirBnB insisted on my Card Details which I was reluctant to give due to all the *******ion in SA. A week and a halve before our due date my Father had an accident. We contacted the Owner and indicated that we would not be able to travel with my Dad from East London to Simbithi in Natal. It was agreed that if we could produce a medical certificate to the effect the money would be refunded. That is in terms of the conditions of AirBnB. We were very grateful. The medical certificate was submitted to the Owner of the Establishment as well as AirBnB. The conditions of AirBnB is that the balance of the money was payable on arrival. The balance was deducted from my card before arrival contrary to their own conditions. AirBnB initially indicated that we could expect a full refund based on the medical certificate. Once everything was submitted this did not transpire. They then offered a voucher to the full amount. Although this is not acceptable we decided to go along, only to be told afterwards that they are only prepared to refund R1 500.00. This is totally unacceptable. My first reaction was to forward this to the Consumer Regulating Board. Problem is that AirBnB is not registered in SA and it would be a waste of time.