Terrible service

I booked a round trip from South Africa to Ireland in April this year. We were to leave on 13 June and return on 11th July. That process went well. Because of COVID I paid R 4 000 to be able to change our flights. It later became necessary to bring our return date forward by a week. Has anyone ever succeeded in contacting these people and got a sensible reply?? I tried their app. - I could have lengthened our stay but not shortened it. I wrote my frustration on their app and the response was that their were no flights on 3 or 4th July. I could find plenty! Then I tried their app and got a reply- There are no live operators here. Phone back in working hours. This was at 11 a.m in the morning and I would have been happy to speak to a dead operator at that stage. I have tried their Cape Town number on numerous occasions but nobody answers.