Mango Airlines complaint

Prior Lockdown, I booked two tickets to Cape Town. After the president put the country on Lockdown, I have been trying to postpone my booking with the Airline but with no luck. When I call, they refer me to the website, when I go to the website, the booking reference cannot be traced. The flight was booked for the 16/04/2020 and to date, I haven't received any correspondence with the Airline. ***, flight No JE135.