Visas & Passports Unlimited has advised that there is currently a delay in South Africa in the availability of visa appointments for the USA.
The first available appointments are currently:
Johannesburg – 20 February 2019
Durban – 30 January 2019
There are no slots available at the American embassy in Cape Town at this time.
Visa companies can request expedited appointments and look for earlier slots on behalf of travellers, although the outcome is not guaranteed.