Eskom's website and its MyEskom Customer app were still offline on Saturday afternoon in the wake of what the power utility has described as a " major incident" at one of its key IT data centres on Wednesday morning.
The utility's separate load shedding website, however, is working.
In an update on Saturday, Eskom said it is still in the process of restoring functionality to its systems.
"We had estimated that Eskom would restore its systems by midnight last [Friday] night. Whilst a significant number of the most critical functions have been recovered, restoration of some of the systems that support our customer engagements have been delayed," it said in a statement.
The utility said that while customers could still log faults via its Eskom call centre, these systems were slower than normal and service delays were "inevitable".
"It also needs to be noted that at this point, the call centres are unable to deal with commercial (billing, payment, etc) queries; and the self-service channels (CS Online and the MyEskom Customer App) are also still affected."
Eskom said that power systems – including power stations, transmission system, and control centres, were not affected by Wednesday's incident.
The utility separately downgraded rotational load shedding from stage 2 to stage 1 at noon on Saturday, due, in part, to the successful synchronisation of Koeberg's Unit 1 to the grid.