Poor customer service

After many attempts at being heard by Comair, I want to report the poor customer service received from British Airways Comair. I tried to exchange some air tickets, which I booked on Kulula via Discovery Vitality during the first hard lockdown in 2020. It took 6 weeks to exchange the tickets for a trip in May 2021. When chcking in, my flight was not confirmed and the flights were full. I therefore needed to book an additional flight to get from Cape Town to Durban via Johannesburg on Kulula at an additional cost. I have also lost the value of the flight that was not confirmed. I complained to Comair on 7 May 2021 and to date they have not reviewed my complaint or tried to resolve it. Besides the additional cost, time and stress of changing my travel plans, it is arrogant of Comair to think that a customer complaint is not worth investigating. When there is a choice of travel partner, don't choose British Airways.