Bad Service towards disability clients

Yesterday I made a flight booking for my fiance, Ms Lucille Kumar on the 15h30 flight from Johannesburg to Cape Town. We afterwards contacted the call centre in order to make arrangements for wheelchair assistance. Due to the call being made after 17h00, were we advice that Kulula cannot guarantee wheelchair assistance. Today I was advice by a Call Centre staff member that Kulula cannot assist Ms Jumat, who is amputated on the one leg, with wheelchair assistance at the airport. This even though that Ms Jumat is making use of her own wheelchair. We were also requested that Ms Jumat should rather take a flight on a different date, in order to allow for wheel assistance. This is however the first time to hear that an airline company is saying this towards disable passengers. As far as we know has no other airline company state this towards disable passengers. We are not sure if any other disable passengers had the same experience with Kululu airline. The airline must definitely look at their policies and procedures towards disable passengers.