AirBnb and Lucinda host

So I booked a place in Desember already. Jist to find out three days before book in that my booking was canceled. Because I didn't make a last payment. They have emaild me but I don't go into my emails every day. I had a few declined messages from my bank but it didn't spesify who wants to deduct money from my account so I didn't know it was them. The host Lucinda refuses to give me back my R6970.30. She already have put someone in the unit so it's not like she lost anything. But still she refuses to give me back my money. I can't see how anyone can just cancel my entire yearly holiday just like that and then refuses to give me back my money. I spoke to the host on friday the 10th and asked her when are they going to deduct the outstanding amount. She didn't know. Couldn't they just have called me. I mean this is totally unacceptable. That's my money and now I have to stay home and cancel my holiday. I think it's very unprofessional and utterly bad. How can I go to work to just atleast get my money back?