No refund received yet after cancellation after 3 weeks.

I made a booking in January, and cancelled the booking early October. I has been 3 weeks and I still have not received my refund. First they said, 10 business days and when I spoke to them after that I was told 5-15 business days. It has been 15 business days and still no refund. I am struggling to get hold of them as they are not responding to my messages. I will never book through AirBnb again. The service is absolutely ****. They are always fast to take money, but there is always an issue when money has to be taken back. I am still way early with my cancellation and they still deducted R900 from they amount paid.