According to Fin24, Matsaung's services were terminated following an altercation between him and Financial Mail's Deputy Editor Sikonathi Mantshantsha.
"Eskom condemns Matsaung's behaviour in the strongest terms possible. We wish to convey our unreserved apologies that this unfortunate incident occurred," Eskom said in a statement.
The hearing will now be postponed until a new evidence leader is appointed.
They said they expected the process to take up to three days to finalise.
Matsaung was working o the case where Koko is believed to have used his influence to award contracts to Impulse where his stepdaughter, Koketso Choma, was a director and 35% owner.