Terrible service and false advertising

I am one of the many South Africans who have had to reschedule their travel plans due to the COVID-19 preventative measures. After the airline proudly and widely announced that they would allow customers to change their flights without having to pay I attempted to. To my surprise, this was not the case and an amount was charged to my credit card. I have been trying for 4 days to call all their call centre numbers and no one bothers to answer. I have also sent emails but still no response.