Shocking service from Booking.com

I own a flat in Port Elizabeth on the beachfront and someone made a booking through Booking.com. The guest stayed in my flat in December 2019 and I still have not received payment from Booking.com. In December 2020 I received an email with a remittance advice from them saying that the amount of R8685.16 had been paid into my account on 28 November 2020. Despite numerous calls to them I am told that it has been referred to the finance dept and that I must be patient. I cannot get to speak to anyone from that department and now I am at my wits end. I do not use them for bookings anymore but I can get no further and I think I have been patient for far too long.