Won't pay me my money back after they stuffed up!

I'm reviewing their website customer service. I placed an order for an item that had a 3-week wait. A day or 2 before the item was due to be delivered, they called and informed me that no one in the country had stock and that I would be refunded. According to their payment procedure, it can take 10 days (despite it being a Zapper payment which can be done through the app - immediately). After the 10th day, I mailed them to which I received no response with the 48hours that the automated response tells you about - so I called them. I was then informed that the money was sitting on my account and they needed my banking details - Annoying that no one called but understandable that maybe they didn't know how to refund through Zapper and needed to EFT me. I sent them my banking details and waited. 4 days later, I got another call from someone responding to my original mail (7 days later!) she said that I needed to give them proof of my bank account and a copy of my ID... FOR MY OWN MONEY that THEY have taken from me. Also, NOWHERE on their website does it say anything about needing documentation to do a refund so now I have to wait a FURTHER 7 days for MY money!!! We're approaching a month which could have been much longer if I didn't keep following up. Unacceptable!