Quite agree about likely numbers not reporting it and that a high number of people suffered from it. On the other hand most people we spoke to said they were fine after 24 hours, and that was certainly our experience. A few like you were poorly for longer, but seemed to be in the minority. I was OK, my husband had it for a few hours, but immodium stopped it - no antibiotics. He was quarantined for the last day.
I wonder if there were 2 separate things - SA water causing a little bit of a GI upset, and some sort of virus causing longer illness and needing antibiotics to clear it.
Interesting to hear that now the bottled water has been changed, everything seems to be back to normal.