Covid ticket

I had made a booking for me and my son to fly to Johannesburg in July 2021 from East London. We went into lockdown and I made and enquiry about my ticket what will happen to it. I was told that my ticket will be valid for 2 years this was in writing. When I now want to use my ticket, I was first told that my ticket expired 30 June 2022. Upon further discussion via email I was later told my ticket expires on the 16th May 2023 as that was my initial booking date. My problem now is that if I want to use my ticket I’m expected to pay over R2000 which does not make sense to me because it’s similar to booking a new flight, I’m been charged for rebooking fees as if it was my fault that I couldn’t fly. They are also not willing to give me a refund claiming my tickets are non-refundable which on my electronic ticket it doesn’t say that. If I can’t fly with those tickets then they must give me back my money. This is soo frustrating!