Fast Jet mistreats disabled client with baby

My sister who is deaf booked a ticket on Fast Jet over a month ago and today she arrives at the airport in Bulawayo and as she is taken off the flight because the flight is overbooked. She is deaf and with baby too. Such poor treatment of vulnerable people. She also then had to fight for airline to arrange transportation for her home and they are refusing to transport her the following day. They should actually have put her up since she didn’t do anything wrong but actually followed their systems. I am actually so appalled.