Zasttra.com not honouring placed and paid for orders

On 16 March 2018 I ordered (and paid for) reusable nappies on the Zasttra.com website. On 18 March 2018 I received an email saying that they are out of stock for my order and that I must reply with my bank details for a full refund. I did this and waited. On 22, 23, 24 & 25 March 2018 I sent them emails asking to be informed about the progress of my refund. I am still being ignored.