Complaint - wheelchair assistance for a 89 year old lady

I booked my Mom with full wheelchair assistance on a flight to East Londen on 3 May 2023. When she arrived there - nobody assisted her - she did not know where to go and walked back to the aircraft at some point. My Mom is 89. When she ultimately got to the inside of the building she did not know where to go. My nephew who was waiting for her saw all of this. He asked the security person where they were standing to assist - this one was not interested. Surely the cabin crew should have never allowed my Mom to get off the aircraft without the assistance? I sent 2 emails to ask that somebody must call me to discuss - no response - telephonically there is no option for complaints? My Mom is flying back tomorrow and I so worried that she will be left on her own in Johannesburg to find her way. Seems the service is deteriorating now that they have the not much competition. I would still want to discuss with somebody at FlySafair.