************** against disabled passenger

I recently placed a booking on Safair for 3 people to Cape Town on 15 Nov, with return on 22 Nov. One of the passengers is disabled and always travels with a mobility s******. We have travelled this way for 20 years with no problems experienced. The mobility s****** has a dry cell battery. When we contacted Safair for special assistance for the disabled passenger they cancelled our booking. The passenger requires help to get to the plane, but can walk from the door to her seat. She cannot climb the stairs. We have travelled with Kulula and Mango previously without any issues. Safair say the s****** is too heavy and they cannot accommodate her in any way. We offered to pay extra luggage fees but they said no ways. We have booked all our accommodation in Cape Town and the disabled traveller has work commitments in Cape Town which cannot be cancelled. Kind regards Jill Murray ***