Lost over £1000 through this service

I booked accommodation for London in June 2022. However , since Im from South Africa I needed a Visa. Adverti*****ts

My visa was delayed , and my Airbnb host whom I communicated all this to, refused to refund me . I negotiated with him , and he suggested that I cancel the booking so that its available. He agreed that should there be any booking ? He would refund me . In addition, he would host me if the visas came through and the place wasnt booked. My visa came through , and he agreed to host me . The day of my flight to London , he changed his mind , refunded me only £350 and still made other bookings. This was unbelievable, not only did he change his mind, he profited over my visa delay and took advantage of the cancellation which he suggested . I have tried to report him to Airbnb and they havent done anything. I paid over £1500 for the booking , and this guy took so much of it , and still reserved other bookings after the cancellation