NO SERVICE FROM KULULA.COM

My parents book tickets from PE to Durban last year and these were cancelled due to lockdown. The money they paid was put into a travel bank account. We have been trying to book new flights with Kulula but are not getting anywhere. I called Kulula and got through after waiting for 10 minutes on hold. I requested the flights etc and the operator said BA would give me a call with a quote. Over a week later and nothing. Tried calling Kulula again, sat on hold for 15 minutes and eventually gave up. I have emailed Kulula twice with no reply. The second email came back with a notification that my email was deleted without being read. I have tried to do the bookings online but there is no option to use your travel bank account. This service, or lack thereof is disgraceful. I have been on the BA website too and there are no options to use your travelbank account. How on earth are we supposed to book flights.