I was attracted to this thread as an acquaintance of mine is on the opposite side of this experience. In JNB trying to get back to Canada yesterday. Only received an alert on their phone (see attachment) - they were offered a route via Germany 2 days later after sitting on the phone (non-status) for 4 hrs with UA customer service (not sure which number/region they called) or what compensation was offered for the disruption. Considering a sold-out flight impacts ~360 passengers (in one direction) so 720 for an out and back. It must a logistic nightmare and I wouldn't wait on the phone call from UA.