Maybe this is fall-out from the recent election. Didn't ANC gain control of KZN? In which case maybe Ulundi will no longer be the "seat of power" for the province, so no need to service that particualr village. If the new KZN governemnt has decided it no longer needs a private fleet of aircraft, and have cancelled the management contract with Airlink.....
Still, unless the pilots were employed as independent contractors or similar, I don't think they could be fired out of hand. Sounds like one for ALPA or a decent labour lawyer.