Very poor customer service

I am flying from Cape Town to OR Tambo tomorrow. I have tried reaching the call centre at least 8 times. On average I have held on for 10 minutes. Then it cuts off so I have not been able to reach anyone. I tried sending a message online but received no response. When I tried to check in online, I received an error message. When I tried on the app, I received a message that the booking has no flight eligible for check in. I understand the new Covid restrictions put pressure on their systems but they should make a plan. The customer service is terrible.