Flight changes on Mango

Booked flights on Mango in September, Durban to Cape Town return. Time of flight from Durban to Cape Town was changed by 15 minutes. No big deal. I understand that there are limited flights during Level 1 lockdown. Time of flight from Cape Town has been changed from 13.15 to 7.00 on Sunday which is absolutely unsuitable. SMS informing me of flight change gives a phone number which I have called twice now, second call after 20 minutes of waiting ends without chatting to an agent. Both did. Not happy with this lack of service.