can't get hold of Qantas call centre to find out about cancelled flight - AWFUL

Awful custom service. We are due to fly to Australia on Friday, we get an SMS on the night of Sun 24 Feb saying that our connecting flight back home from Joburg to Cape Town on SAA has been cancelled, to contact Qantas. Yesterday we called a few times and on 2 occasions held on for 45mins but still no answer. We called a few times today - same thing. We sent an email last night but still no answer. How are we to know how we will get home and what arrangements to make for our pets?! We're at our wits end not to mention that those calls on a cellphone have so far cost a small fortune. I do like flying on Qantas if only their call centre in SA would live up to the inflight service!