Finally received my order. Once I had the local tracking number, I went to my local post office. Customer Services hadn't told me where it was and neither had the tracking, but I had a reasonable guess because this one is the closest post office to me. I was right.
Customs cost - R191. Total order cost - R1484. Cost per KG - R148.4.
Lessons for future - if you order from MyProtein, have them deliver to an address where you will be during the day. If you are lucky enough that they deliver it to you (still not 100% convinced that they tried to deliver to me at all), then your problem is solved.
If that for some reason doesn't work, good luck getting your local tracking number. It is the most difficult and frustrating part of the process. If you manage to get it, don't trust what the post office tracking site says, because it is wrong 95% of the time. Just go to your post office with the local tracking number and ask them if they have it.